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<Q SC3 EX SCIO SINCLHYD>
<N HYDROSTATICKS>
<A SINCLAIR GEORGE>
<C SC3>
<O DATE 1672/1683>
<M MEDIUM PRINTED>
<D CSC>
<V PROSE>
<T SCIENCE OTHER>
<G X>
<F X>
<W WRITTEN>
<X MALE>
<Y X>
<H HIGH PROF>
<U NET PROF>
<E X>
<J X>
<I X>
<Z EXPOS>
<S SAMPLE X>

[^SINCLAIR, GEORGE.
THE HYDROSTATICS, OR THE WEIGHT, FORCE, AND PRESSURE AND 
SENSIBLE EXPERIMENTS. TOGETHER WITH .. A SHORT HISTORY OF
COAL. EDINBURGH 1672.

NATURAL PHILOSOPHY IMPROVEN BY NEW EXPERIMENTS.
EDINBURGH 1683.

SAMPLE 1: PP. 1.1-21.32      (HYDROSTATICS)
SAMPLE 2: PP. 109.21-119.32 
SAMPLE 3: PP. 197.1-201.18   (NATURAL PHILOSOPHY)
SAMPLE 4: PP. 207.1-217.16
SAMPLE 5: PP. 224.4-227.28^]

<S SAMPLE 1>
<P 1>
[}HYDROSTATICAL
THEOREMS, 
CONTAINING SOME USEFUL PRINCIPLES IN ORDER
TO THAT EXCELLENT DOCTRINE, ANENT
THE WONDERFUL (^WEIGHT^) , (^FORCE^) , AND (^PRESSURE^) OF
THE WATER IN ITS OWN ELEMENT.}] 

[}THEOREM I.
IN AL FLUIDS, BESIDES THE FIRST AND VISIBLE HORIZONTAL          #
SURFACE, 
THERE ARE MANY MOE (^IMAGINARY^) , YET REAL.}]
Figure I.

   For the better understanding the 
following Experiments, it is 
needful to premit the subsequent 
Theorems; the first whereof
is, that in all Fluid bodies, 
such as Air, Water, and Mercury,
or any other liquid, there is besides
the first and visible surface, 
innumerable moe imaginary, under
that first, yet real, as may
be seen from the following Schematism, which represents 
a Vessel full of Water, where besides the first surface  
<P 2>
ABCD, there is a second EFGH, and the third IKLM, 
and so downward, till you come to the bottom. This 
holds true, not only in Water, but in Air also, or in any 
other Fluid body whatsoever. I call the under-surfaces 
imaginary, not because they are not real; for true and real 
effects are performed by them; but because they are not 
actually distinguished amongst themselves, but only by the 
Intellect. 

[}THEOREM II.
IN ALL FLUIDS, AS IT IS NEEDFUL TO CONCEIVE HORIZONTAL 
PLAINS, SO IT IS NEEDFUL TO CONCEIVE PERPENDICULAR 
PILLARS, CUTTING THESE PLAINS AT RIGHT ANGLES.}]
Figure I.

   This Proposition is likewise needful for understanding 
the following Doctrine, anent the Pressure of the 
Water: for in it, as in all Fluids, though there be not 
Columes or Pillars actually divided, reaching from the 
top to the bottom, yet there are innumerable (^imaginary^) ,
which do as really produce effects by their pressure, as if 
they were actually distinguished. These (^imaginary^) Pillars
are represented in the first Schematism, one whereof is 
AEINOPQ, the other BFKRT, and so forth. 

[}THEOREM III.
THERE IS A TWOFOLD BALLANCE, ONE (^NATURAL^) , 
ANOTHER (^ARTIFICIAL^) .}]

   By the (^Artificial Ballance^) , I understand that which the
Mechanicks call (^Libra^) , which Merchants commonly 
use. By the (^Natural Ballance^) (which for distinctions cause
<P 3>
I so nominat) I mean, (^v.g.^) a (^Siphon^) , or crooked Pipe,
wherein water naturally ascends or descends, as high or low 
in the one Leg, as in the other, still keeping an evenness,
or likeness of weight.

[}THEOREM IV.
FLUID BODIES COUNTERPOISE ONE ANOTHER IN THE (^BALLANCE^) OF 
(^NATURE^) , ACCORDING TO THEIR (^ALTITUDE^) ONLY.}]

   This Theorem will appear afterwards most evident, 
while we pass through the several Experiments; and 
it is of special use for explicating sundry difficulties that 
commonly occur in the (^Hydrostaticks^) . The meaning of it 
is shortly this: while two Cylinders of Water are in the 
opposite Scales of the (^Natural Ballance^) , they do not       #
counterpoise
one another according to their thickness: for 
though the one Pillar of Water be ten times thicker, then 
the other, and consequently heavier, yet is it not able to 
press up the other, that's more slender, and so lighter, 
beyond its own hight: and therefore they weigh only according
to their (^Altitudes^) . 

[}THEOREM V.
IN ALL FLUIDS THERE IS A PRESSURE.}]
Figure I.

   This is true not only of the Elements of Air, and Water, 
while they are out of their own place (as they 
speak) but while they are in it. For Air and Water, being 
naturally indued with weight, the second foot cannot 
<P 4>
be under the first, unless it sustain it: if this be, it must 
necessarily be prest with its burden. So this Water being 
naturally a heavy body, the foot I cannot be under E, unless
it sustain it, and be prest with the burden of it; the 
foot N, being burdened with them both, From this Pressure,
which is in Air, ariseth a certain sort of force, and 
power, which may be called (^Bensil^) , by vertue whereof, a 
little quantity of Air, can expand and spread out it self, to a
very large quantity, and may by extrinsick force be reduced
to that small quantity again. Though this expansive 
faculty be evident in Air, yet it is scarcely discernable in 
Water, unless it be very deep parts, near the bottom, 
where the Pressure is great. This Pressure is not of the 
same Degree in all the parts, but is increased and augmented,
according to the deepness of the Air, and Water: for 
the Air upon the tops of Mountains, and high places, is 
thought to be of less Pressure, then in Valleys: and Water 
is of a less Pressure, ten or twelve foot from the top, 
then twenty or thirty. So is the Water N, under a far 
less Pressure, then the Water, P or Q. 

[}THEOREM VI.
THE PRESSURE OF FLUIDS IS ON EVERY SIDE.}]
Figure I.

   The meaning is, that Air and Water presseth not only
downward, but upward, not to the right hand only, 
but to the left also, and every way. So the foot of water K, 
not only presseth down the foot R, but presseth up the 
foot F, yea presseth the foot I, and the foot L, with the 
same weight. And the first imaginary surface, is as much 
<P 5>
prest up, by the water IKLM, as it is prest down by the 
water EFGH. Upon this account it is, that when a 
Sphere, or Glob is suspended in the midle of Water, or Air, 
all the points of their surfaces are uniformly prest. After 
this manner, are our bodies prest with the invironing Air, 
and the man that (^dives^) , with the ambient and invironing 
Water. 

[}THEOREM VII.
ALL THE PARTS OF A FLUID IN THE SAME HORIZONTAL LINE, 
ARE (^EQUALLY^) PREST.}]
Figure I.

   The meaning is, that the foot I, is no more prest, 
then the foot K: neither is the foot L, more burdened,
then the foot M. The reason is, because each of 
these feet, sustains the same weight: for EFGH are all 
of them, of the same burden: therefore all the parts of a 
Fluid in the same Horizontal surface, are prest most equally. 
This holds true in Air, and Mercury, or in any other 
Liquid also. 

[}THEOREM VIII.
THE PRESSURE OF FLUIDS SEEM TO BE ACCORDING TO 
(^ARITHMETICAL PROGRESSION^) .}]
Figure I.

   The meaning is, that if the first foot of Water, have 
one Degree of Pressure in it, the second must have 
only two, and the third must have only three, and so forth, 
<P 6>
which appears from the Schematism: for the first foot E, 
having one Degree of weight, and the second foot I, having 
of its self as much, and sustaining E, it must have two 
Degrees, and no more. So the foot N, sustaining two 
Degrees of Pressure from I and E, must have the weight 
only of three Degrees, O of four, P of five. It's evident
also from Experience, for while by the Pressure of Water, 
Mercury is suspended in a glass tub, we find, that as the 
first fourteen inches of Water, sustains one inch of Mercury, 
so the second fourteen inches sustains but two, and the 
third, but three. But if the Pressure were according to 
(^Geometrical progression^) , the third foot of Water ought to
sustain four inches of Mercury, the fourth, eight; the fifth,
sixteen, (^&c.^) which is contrary to Experience. 
 

[}THEOREM IX.
IN ALL FLUIDS THERE IS A TWOFOLD WEIGHT, ONE (^SENSIBLE^) ,
THE OTHER (^INSENSIBLE^) .}]

   The first is common to all heavy bodies, which we 
find in Water, while we lift a Vessel full of it from 
the ground. The (^Insensible weight^) of Water, and Air,
 or of any other Fluid, can scarcely be discerned by the 
senses, though it be as real, as the former, because the 
Pressure is uniform. By vertue of the second, bodies naturally
lighter than Water, are driven from the bottom to 
the top, as (^Cork^) . So, a man falling into a deep Water, 
goes presently to the bottom, and instantly comes up again. 
Here is a natural effect, which cannot want a natural cause;
and this can be nothing else, but the Pressure of the Water, 
by vertue whereof he comes up, and yet he finds nothing
<P 7>
driving him up, or pulling him up. Therefore, 
there is in all Fluid bodies, an (^Insensible^) weight, as      #
there 
is one (^Sensible^) ; seing the man that (perhaps) weighs       #
seventeen 
Stone, is driven up fifteen or sixteen fathom by 
it. And it must be very considerable, and exceed the 
weight of the man, seing it is able to overcome such a 
weight. So are vapours and smoke driven upward by the
(^Insensible weight^) of the Air, and by that same weight, do 
the Clouds swim above us. 

[}THEOREM X.
THE INSENSIBLE WEIGHT OF FLUIDS, IS ONLY FOUND BY SENSE, 
WHEN THE PRESSURE IS NOT UNIFORM.}]

   For understanding of this Proposition, I must suppose 
somethings that are possible, but not practicable. 
Put the case then, while a man opens his hand, the Air 
below were removed, he would scarce be able to sustain 
the weight of the Air, that rests upon the  Palm above:
or if the Air above were annihilated, he would not be able 
to bear down the weight that presseth upward. Or, while 
a (^Diver^) is in the bottom of the Sea, if it were possible to
free any one part of his body from the Pressure of the Water, 
suppose his right arm, I doubt not, but the blood 
would spring out in abundance from his finger-ends: for 
the arm being free, and the other parts extremly prest, 
the blood of necessity must be driven from the shoulder 
downward, with force, which cannot be without considerable 
pain. It is evident also, from the application of 
the (^Cuppin-glass^) , which being duely applied to a mans 
skin, causeth the Air to press unequally, the parts without,
<P 8>
being more prest, than the parts within, in which 
case the unequal Pressure causeth the pain, and so is found 
by sense. 

[}THEOREM XI.
A CYLINDER OF WATER, OR OF ANY OTHER FLUID BODY, LOSETH OF ITS 
WEIGHT, ACCORDING TO ITS RECLINATION FROM A (^PERPENDICULAR^)
POSITION, TOWARDS AN (^HORIZONTAL^) OR 
LEVELL SCITUATION.}]

   For understanding of this, consider that while a 
Pipe full of Water stands perpendicular, the lowest 
foot sustains the whole weight of the Water above it:
but no sooner you begin to recline the Pipe from that Position,
but assoon the Pressure upon the lowest foot grows
less; So that if the lowest foot, in a perpendicular position, 
sustained the burden of ten feet, it cannot sustain 
above five or six, when it is half reclined. A certain evidence
whereof is this, the more a Cylinder of Water is 
reclined towards the Horizon, or Level, it takes the shorter 
Cylinder of Water to counterpoise it, as is evident in          #
(^Siphons^) . 
For, though the one Leg, be sixteen inches long, 
and the other but six; yet a Cylinder of Water six inches 
long, will counterpoise a Cylinder of sixteen. But this
cannot be, unless an alteration be made in the Pressure.
For, how is it possible, that a Cylinder of Water can 
sometimes be in (^aequilibrio^) with a lesser, and sometimes 
with a greater weight, unless the Weight, and Pressure of 
it, be sometimes more, and sometimes less? When I say 
a Cylinder of Water loseth of its weight by reclination, 
it is to be understood only of the (^Insensible Weight^) : for
<P 9>
the (^Sensible Weight^) is unchangeable, seing it is alwayes a
Pillar of so many inches, or feet. Now the true reason, 
why the Pressure upon the lowest foot grows less, is this;
the more the Pipe is reclined, the more weight of the 
Cylinder rests upon the sides of the Pipe within; by 
which means, the lowest foot is eased of the burthen, and 
is altogether eased, when once the Pipe lyes Horizontal. 

[}THEOREM XII.
ALL MOTION IN FLUIDS, IS FROM THE UNEQUAL PRESSURE    
OF THE HORIZONTAL SURFACE.}]
Figure I.

   For understanding this, I must distinguish a twofold motion
in Fluids; one (^common^) , another (^proper^) , by vertue
of the first, they incline, as all other heavy bodies, to 
be at the center of the Earth. It is evident in the motion
of Rivers, which descend from the higher places to the          #
valleys, 
even by vertue of that tendency they have to be at 
the (^center^) . By vertue of the second, they incline to move
every way; not only downward, but upward, hither and 
thither. This sort of motion is peculiar, and proper only 
to Fluids; and it is that which is spoken of this Theorem. 
I say then, that all motion in Fluids, is from the unequal 
Pressure of the Horizontal surface. For put the case 
A, were more prest then B, (^e.g.^) with a stone, then surely   #
as 
the part A descends, the other part B will ascend, and so
will C and D rise higher too. Suppose next, the part A 
were fred of the Pressure of the Air, then surely in the 
same instant of time, would the part A ascend, and the 
parts BCD descend. As this Proposition is true in order 
<P 10>
to the first and visible surface ABCD; so it is true in order 
to the (^imaginary^) surface IKLM; for put the case the 
space I, were filled with a body naturally heavier then 
Water, as lead or stone, then behoved that part of the surface
to yeeld, it being nore prest, then the part of the same 
surface K. Or if the space K were filled with a body naturally
lighter then water, as Cork, then ought the water 
R to ascend, it being less prest, then the water N or S.

[}THEOREM XIII.
A BODY NATURALLY HEAVIER THEN WATER, DESCENDS; AND 
A BODY NATURALLY LIGHTER, ASCENDS.}]
Figure I.

   For understanding of this, let us suppose the quadrat 
space E, to be filled with a piece of Lead or Iron. I 
say then it must go down to I; and the reason is, because 
the quadrat foot of Water I, is more pressed then the 
quadrat foot of Water K. To illustrat this, let us suppose 
that each quadrat foot of this Water weights a pound,
and that the heavy body existing in E, weights two 
pound. If this be, the foot of Water I, must yeeld, seeing
it is more prest then K: upon the same account must 
the Water N yeeld, and give way to the Stone, seeing
it is more prest then R. For according to the twelfth
Theorem, (^There cannot be unequal Pressure upon a surface, 
unless motion follow^) . 
   For understanding the second part, let us suppose the 
space R, to be filled with a piece of Cork, that is             #
specifically
or naturally lighter then Water. I say then, it 
must ascend to the top B; and the reason is, because the 
quadrat foot of Water K, is more prest upward, then the 
<P 11>
quadrat foot of Water I, or L is: but this cannot be in 
Fluid bodies, unless motion follow thereupon. I say, it 
is more prest up, because R being lighter then N, or S, 
it must press with greater force upon K, then S can do 
upon L, or N upon I. It is still to be remembred,
(^That Fluids presseth with as much strength upward, as         #
downward^) ,
according to the sixth Theorem; and that an Horizontal 
surface doth as really suffer unequal Pressure from 
below, as from above. 

[}THEOREM XIV.
BODIES NATURALLY LIGHTER THEN WATER, SWIM UPON 
THE SURFACE AND TOP.}]
Figure I.

The reason of this Proposition must be taken from 
the nature of an (^equipondium^) , or equal weight. For 
without doubt, there is a counter-ballance between the 
Pressure of the Water, and the weight of the body that 
swims. To make this probable, let us suppose there were 
a piece of Timber in form of a Cube, six inches thick every
way, without weight. In this case, the under-surface 
of that four-squar'd body,  being applied to the surface of 
the Water A, would ly closs upon it, as one plain Table 
lyes upon the face of another, without any pressure: and 
it being void of weight, the part of the surface A, would 
be nor more burdened, then the next part B adjacent, 
whence no motion would follow. Here is no (^equipondium^) ,
or counter-ballance. 
   Secondly, let us suppose the said body to acquire two 
ounces of weight, then it follows, that it must subside, 
and sink two inches below the surface ABCD; and that 
<P 12>
so far, till it come by vertue of its new acquired weight, to 
a counter-ballance with the Pressure of the Water. Which 
Pressure is nothing else, but as much force or weight, as is 
equivalent to the weight of Water, that is thrust out of 
its own place, by the subsiding and sinking of that body, 
two inches. 
   Thirdly, let us suppose the same body to acquire other 
two ounces of weight, then must it subside other two 
inches. Lastly, let us suppose that it acquires six ounces
of weight, then it follows that the whole body sinks, so 
far, I mean, till its upmost surface be in an (^Horizontal      #
line^)
with the surface of the Water ABCD. Here it swims 
also, because the weight of it becomes just the weight of 
so much Water, as it hath put out of its own place. I say, 
it must swim, because if the Water I, was able to sustain 
the  Water E, which is put from its own place, surely it 
must be able to sustain that body also, that did thrust it 
from its own place, seing both are of the same weight, 
namely six ounces. In this case, the body immerged, 
and the water wherein it is drowned, become of the same 
weight (^specifically^) , seing bulk for bulk is not the same 
weight. To make this body (^specifically^) , or naturally       #
heavier
then Water, and consequently to sink to the bottom,
nothing is required, but to suppose that it acquires 
one ounce more of weight, which done, it presently goes 
down, I, being nore burdened then K. Note by the 
way, a twofold weight in heavy bodies, one (^individual^) ,
the other (^specifick^) , and that two bodies agreeing in       #
(^individual^)
weight, may differ in (^specifick^) weight. So a pound 
of Lead, and a pound of Cork, agree (^individually^) , because 
they are both 16. ounces: but they differ (^specifically^) ,
because the one is naturally heavier then the other. 
<P 13>
[}THEOREM XV
NO BODY THAT FLOTS ABOVE WATER, EVEN THOUGH ITS UPPER 
SURFACE BE LEVEL WITH THE SURFACE OF THE WATER, CAN EVER 
BE MADE TO SWIM BETWEEN THE TOP AND THE BOTTOM.}]
Figure I.

   For clearing this Proposition, let us suppose F to be a 
four-square piece of Timber, of the same (^specifick^) and 
natural weight with Water, and consequently its upper surface
to be level with the surface of the Water ABCD. I 
say then, if it be prest down to R, it shall arise thence, and 
never rest till it be where it was, namely in F. The reason 
seems to be this, because the four-squar'd body of Water R, 
is really heavier, then the four-squar'd piece of Timber F. 
If this be true, it follows of necessity, that it must ascend: 
for if the Timber existing in R, be lighter than Water R,
the Water T must be less prest, then the Water O, or the 
Water V; whence (according to the twelfth Theorem) 
(^motion must follow^) . Again, if the Timber R, existing in    #
the
Water R, be lighter then the same Water is, then must 
the Water K, be more prest up then the Water I, or L;
whence yet, according to the same Theorem, (^motion must
follow^) . If it be said, that the Timber F, is of the same 
weight with the Water R, because, it being equal in 
weight with the Water F, which it hath thrust out of its 
own place, it must also be equal in weight to the Water R, 
seeing F and R being of the same dimensions, are of the 
same weight. There is no way to answer this difficulty, 
unless I say the four-squar'd body of water R, is really and 
truly heavier then the four-squar'd body of Water F. The 
<P 14>
reason seems to be, because the Water R, is under a greater 
Pressure, then the Water F; and by vertue of this 
greater Pressure, there are really (^moe parts^) of Water in    #
it,
then in F; therefore it must be heavier. Even as there are
far moe parts of Air, in one cubick foot near the (^Earth^) ,   #
then 
in six or seven near the (^Atmosphere^) . Hence it is, that 
a pint of Water taken from the bottom of the Sea, fourty 
fathom deep, will be heavier, I mean in a ballance, then a 
pint taken from the surface. Take notice, that when the 
vessel in once full at the bottom, the orifice must be closely 
stopped, till it come to the top: otherwise the parts that 
are compressed at the bottom, namely by the weight of 
the superiour parts, relaxes themselves, before they come 
to the top.

[}THEOREM XVI.
IT IS NOT IMPOSSIBLE FOR A BODY TO BE SUSPENDED BETWEEN 
THE (^SURFACE^) AND THE (^BOTTOM^) .}]
Figure I.

   For understanding this, suppose F to be a four-square
piece of Timber, which though it will not rest but at 
the surface, ABCD, yet may be made to go down of its
own accord, and rest at T, namely, by making it so 
much heavier, as the Water T is heavier then the Water 
F. To know this difference, which is not very practicable; 
the cube of Water T, must be brought from its own place, 
under the same degree of Pressure it hath, and put into the 
Scale of a Ballance, and weighed with the Cube of Water 
F, put into the other Scale. Now if the Water T, be 
half an ounce heavier, then the Water F, then to make 
the Timber F hing in T, it must be made half on ounce
heavier. There seems to be reason for it also; for if a 
<P 15>
Cube of Timber resting in the space T, be just the weight 
of the Water T, the (^imaginary^) surface OTV, is no more
prest, then if T were Water, and  so it cannot go down-ward:
neither can it go upward, seing the under part of 
the Water R, is no more prest up by the Timber T, then 
if the space T were filled with Water. If is be said,           #
according 
to this reasoning, a Stone may be suspended in a deep 
Water, between the top and the bottom, which is absurd. 
I answer, such a thing may happen in a very deep Water: 
For put the case a Cube of Lead twelve inches every way, 
were to go down twelve thousand fathom, it is probable, 
it would be suspended before it came to the ground. For 
coming to an (^imaginary^) surface far down, where the Pressure
is great, a Cube of Water twelve inches thick there, 
may be as heavy (even (^specifically^) ) as the Cube of Lead
is, though the Lead be ten times heavier (^specifically^) ,     #
then
any foot of Water at the top. If Water suffer compression 
of parts, by the superiour burden; it is more then 
probable, that the second foot of Water burdened with 
the first, hath moe parts in it, then are in the first, and     #
the 
thrid moe, then in the second, and so forth; and consequently,
that the second is heavier, then the first, and the 
third heavier, then the second. Now, if this be, why 
may not that foot of Water, that hath sixty thousand 
foot above it, by vertue of this burden, be so comprest, 
that in it may be as many parts, as may counter-ballance a 
Cube of Lead twelve inches every way? If then, that             #
(^imaginary^)
surface, that is sixty thousand foot deep, be able to 
sustain the said foot of VVater, which perhaps weighs 
twenty pound, why may it not likewise sustain the Lead,
that is both of the same dimensions with it, and weight?
<P 16>
Hence it is, that the Clouds do swim in the Air, by vertue
of a counter-ballance: And we see, which confirms this 
Doctrine, that the thinnest and lightest are alwayes farthest 
up; and the thickest and blackest, are alwayes farthest 
down. 

[}THEOREM XVII. 
THE LOWER THE PARTS OF A FLUID ARE, THEY ARE THE HEAVIER,
THOUGH ALL OF THEM BE OF EQUAL QUANTITY AND DIMENSIONS.}]
Figure I. 

   This follows from the former, which may appear a 
Paradox, yet it seems to be true: for though the 
Water Q at the bottom, be of the same dimensions with 
the Water E at the top, yet it is really heavier, which 
happens (as I said) from the superiour Pressure. It is clear 
also from this, namely the Cube of Timber E, which 
swims upon the surface, being thrust down to Q, comes
up to the top again, which could not be, unless the Water 
Q, were heavier than the Water E. I suppose the Water 
E, and the Timber E, to be exactly of the same (^specifick^)
weight, and consequently the surface of the Timber, 
to ly Horizontal with BCD. Now the reason, why the 
Timber ascends from Q to E, is no other then this, namely 
that the one Water is heavier then the other; for the 
under part of the Water P, being more prest up with the 
Timber existing in Q, then with the Water Q it self, it 
must yeeld and give way to the ascent: for if the Cube of 
Timber existing in Q, were as heavy as the Water Q it self,
it would no more press upon P, or endeavour to be up, then 
the Water Q does. 
<P 17>
[}THEOREM XVIII. 
A HEAVY BODY WEIGHS LESS IN WATER, THEN IN AIR.}]
Figure I. 

   This is easily proven from experience; for after you 
have weighed a stone in the Air, and finds it two 
pound, and an half, take it, and suspend it by a threed knit 
to the scale of a ballance and let it down into the Water, 
and you shall find it half a pound lighter.  The question 
then is, why doth it lose half a pound of its weight? I 
answer, the stone becomes half a pound lighter, because
the surface of Water on which it rests, sustains half a pound 
of it: For put the case a stone were resting in R, that weighed
two pound and an half in the Air, it behoved to weigh 
but two pound in this Water; because the Water T sustains 
half a pound of it. For if this Water T be able to 
sustain the Water R, that weighs half a pound, it must 
be also able to sustain half a pound of the stone, being half 
a pound of stone is no heavier, then half a pound of Water. 
Note, that when a heavy body is weighed in Water, it becomes 
so much lighter exactly, as is the weight of the Water 
it thrusts out of its own place. 

[}THEOREM XIX. 
A HEAVY BODY WEIGHS LESS NIGH THE (^BOTTOM^) OF THE WATER, 
THEN NIGH THE TOP THEROF.}]
Figure I. 

   For clearing this proposition, I must suppose from the 
17. Theorem, that the lower the parts of Water 
<P 18>
be, they are the heavier, though all of them be of equal        #
dimensions. 
If then the lowest foot Q be heavier, that is, 
have moe parts in it, then the foot N, it of necessity follows,
that a stone suspended in Q, must be lighter then
while it is suspended in N or I. Because, if a stone be 
lighter in Water then in Air, as is said, even by as much, as 
is the weight of the bulk of Water, that the bulk of the 
stone expells, then surely it must be lighter in the one, then 
in the other place; because suspended in Q, it expells 
moe parts of Water, then while it is suspended in N or I. 
For example, let us suppose the Water N, to weigh eight 
ounces, and the Water Q to weigh nine, then must the 
stone suspended in Q, weigh less by an ounce, then 
suspended in N, seeing as much is deduced from the weight 
of the stone, as is the weight of the Water it expells: but 
so it is, that it thrusts nine ounces of Water out of its own 
place in Q, and but eight in N or I; therefore it must 
be one ounce lighter in the one place, then in the other.
This may be tried, with a nice, and accurat ballance, which 
will bring us to the knowledge of this, namely how much 
the foot of Water Q is heavier, then the Water N or O. 

[}THEOREM XX.
ONE PART OF A FLUID, CANNOT BE UNDER COMPRESSION, 
UNLESS ALL THE PARTS NEXT ADJACENT, BE UNDER 
THE SAME DEGREE OF PRESSURE.}]
Figure I. 

   This proposition may be proven by many instances: 
for when the Air of a (^Wind-gun^) , is reduced to less 
quantity by the Rammer, all the parts are most exactly of 
the same (^Bensil^) . So is it in a Bladder full of wind. It's
<P 19>
true, not only in order to this artificial Pressure, but in     #
order 
to the natural Pressure, and (^Bensil^) of the Air likewise. 
For the Air within a parlour, hath all its parts, under the 
same degree of natural compression: so is with the parts 
of the Air, that are without, and immediatly under the 
weight of (^Atmosphere^) . Its evident also in the parts of
Water: for the foot of Water R, cannot be under Pressure, 
unless the Water S, and N, be under thee same degree of it. 
Though this be true of Fluids, while all the parts
lye in the same Horizontal surface, yet to speak strictly, it 
will not hold true of the parts scituated under divers          #
surfaces;
for without question, the foot of the VVater T, must 
be under four degrees of Pressure, if the VVater R, be 
under three. And if the Air in the lowest story of a building, 
be under six degrees of (^Bensil^) , the Air in the highest 
story must be under five. If a man would distinguish            #
(^Metaphysically^) ,
and subtilly, he will find a difference of this 
kind, not only between the first, and second fathom of Air, 
nearest to the Earth, but between the first, and second foot;
yea, between the first and second inch, and less; much more 
in Water, as to sense. However it be, yet the Theorem
holds true; for we find no difference sensible, between 
the compression of Air in this room; and the compression 
of Air in the next room above it, no not with the 
(^Baroscope^) , or (^Torricellian Experiment^) , that discerns  #
such 
differences accurately. I judge it likewise to be true, in 
order to the next adjacent parts of Fluids of different kinds;
for while a surface of Mercury, is burdened with a Pillar of 
Water, or a surface of Water, with a Pillar of Air, whatever 
degree of weight and Pressure, is the lowest parts 
of these Pillars, the same is communicated entirely, to the 
surfaces, that sustains them. So then, there is as much 
<P 20> 
force and power, in the surface of any Water,  as there is 
Weight and Pressure, in the lowest foot of any Pillar of 
Air, that rests upon it: otherwise, the surface of Water
would never be able to support the said Pillar: for a surface
of six degrees of force, can never be able to sustain a 
a Pillar of Air, of eight, or ten degrees of weight. 

[}THEOREM XXI.
THE PRESSURE OF FLUIDS, MAY BE AS MUCH IN THE LEAST 
PART, AS IN THE WHOLE.}]
Figure I. 

   This Theorem may seem hard, yet it can be made manifest,
by many instances: for albeit the quantity 
of Air, that fills a Parlour, be little in respect of the whole
Element, yet surely, there is as much Pressure in it, as in 
the whole; because Experience shews, that the (^Mercurial 
Cylinder^) in the (^Baroscope^) , will be as well sustained in  #
a
Chamber, as without, and under the whole (^Atmosphere^)
directly; which could not be, unless the small portion of 
Air, that's in this Parlour, had as much Pressure in it, as 
in the whole Element. Besides this, it will be found in a 
far less quantity: for though the (^Baroscope^) were inclosed,
and imprisoned so closs, within a small Vessel, that the  
Air within, could have no communion with the Air without, 
yet the Pressure of that very small quantity, will 
sustain 29. inches of Mercury, and this will come to pass, 
even though the whole Element of Air were annihilated.
This Proposition is likewise evident in order to the Pressure
of the Water: for put the case, the (^Baroscope^) , whose 
Mercurial Cylinder is 29. inches, by the Pressure of the 
<P 21>
Air; were sent down to the bottom of a Sea 34. foot deep, 
within a Vessel, as a Hogs-head, and there exactly inclosed,
that the VVater within, could have no commerce 
with the VVater without, yet as well, after this shutting 
up, as before, other 29. inches would be sustained, by the 
Pressure of this imprisoned VVater, which proves evidently, 
that there is as much Pressure in one Hogs-head full of 
VVater, at the bottom of the Sea, as in the whole Element 
of  VVater, above, or about: for an Element of 
VVater never so spacious, if it exceed not 34. foot in 
deepness, can sustain no more Mercury, then 29. inches 
by its Pressure. Yea, though the Vessel with the                #
(^Baroscope^) ,
and imprisoned VVater in it, were brought above
to the free Air, yet will the VVater retain the same Pressure,
and will (\de facto\) sustain 29. inches of Mercury, provided
the Vessel be kept clos. It is therefore evident, 
that as much Pressure may be in one small quantity of 
VVater, as in the whole Element, or Ocean. 'Tis to 
be observed, that this Theorem is to be understood chiefly
of the lower parts of Fluids; seing there cannot be so 
much Pressure in the VVater P, as in the VVater Q; for 
in effect, there is as much Pressure in the VVater Q, as 
is in the whole VVater above it, or about it. From this 
Theorem, we see evidently, that the Pressure, and (^Bensil^)
of a Fluid, is not to be measured, according to its bulk,
and quantity, seing there is as much (^Bensil^) in one foot, 
nay, in one inch of Air, as is in the whole Element, and as 
strong a Pressure in one foot of VVater, or less, as there 
is in the whole Ocean: therefore the greatest quantity of 
Air, hath not alwayes the greatest (^Bensil^), neither the      #
greatest 
quantity of VVater, the greatest Pressure. But this 
will appear more evident afterwards.

<S SAMPLE 2>
<P 109>
[}EXPERIMENT XIII.}]
Figure 17, 18, 19.

   For making this Experiment, take two (^plain^) Bodies of
Brass, or Marble well polished. Make them of any 
quantity; but for this present use, let each of them be four 
inches broad square wise. Upon the back part, let each 
one have an handle about six inches long, of the same metal, 
formed with the (^plain^) it self, in the founding (if they be 
of Brass) as is represented in this Schematism. When 
<P 110>
they are thus prepared, anoint their inner-sides with Oyl 
or Water, and having thrust the one face alongst upon the 
other, with all the strength you have, till all the four edges 
agree, two whereof are represented by AB, and CD, you 
will find them cleave so clos together, as if they were but 
one Body. The effect is this, that ordinary strength will
not pull them asunder; and that under a surface of Water, 
a stronger pull is required than in the Air. 
   That we may deduce some (^Hydrostatical^) conclusions 
from this Experiment, let us suppose these two (^plain^) Bodies
to be united in the middle of the VVater IKPQ 
that's 34 foot deep, and suspended by a beam or long tree 
TV existing in the Air, near the top of the VVater, by a 
chord SE passing between the middle of the beam, and
the end of the handle at E. Suppose next a great weight 
of Lead R, 350 pound, to be appended to the end of the 
handle at H, of the under (^plain^) Body CDNO. This 
done, I affirm, that the beam TV, neither sustains the under
(^plain^) Body CDNOGH, nor the 350 pound 
weight of lead R, that hangs down from the handle GH.
If it be objected, that the beam supports the upper (^plain^)
Body ABLMFE; therefore it must bear the weight 
also of the under (^plain^) CDNOGH, with the weight R; 
seing they are both united together, and cleave so closs,
as if they were but one Body. I answer, it supports the 
one unquestionably, but not the other. To explicate 
this (^Hydrostatical^) Mystery, I must aver three things;       #
first,
that the inferior (^plain^) is supported by the upward Pressure
of the lower VVater PQNO. Secondly, that the 
burden which the beam sustains, is not the weight of the 
under (^plain^) , but the weight of the 34 foot of Water IK
LM. thirdly, that this weight is exactly the weight 
<P 111>
of the inferior (^plain^) , and Lead R. But is it not more 
easie to say, that the beam supports both the (^plains^) : I
answer, if I say so, I can neither affirm truth, nor speak      #
consequentially,
But may it not be said, that the inferior 
(^plain^) is supported both by the beam, and the lower water 
PQNO? I answer, this is impossible; because one and 
the same weight, cannot be supported totally, by two distinct
supporters. 
   For making these assertions evident, I must suppose the 
superior Water IKLM to be 34 foot deep, and to
weigh, if it were put into a ballance, 400 pound: and which 
is unquestionable, that the said Water rests upon the back 
of the superior (^plain^) LM. I suppose secondly, that the 
lower Water PQNO weighs as much, and thrusts up 
the inferior (^plain^) with as great weight, as the superior
(^plain^) is prest down with, by the superior Water.  This  
is evident from former Experiments. And lastly, I suppose
each (^plain^) to weigh two pound, and the weight of 
Lead R 350. It is to be observed here, that no mistake may 
arise in the calculation afterwards, that though it be said, 
this 34 foot of Water weighs 400 pound, yet in it felt it, 
weighs but 200: but considering the Pressure of the Air 
upon IK, which is as much, it may be truly said to weigh 
400. These things premitted, I say the weight that 
the beam TV sustains, is not the weight of the inferior
(^plain^) , and the Lead R, but 352 pound of the superior
VVater IKLM, and consequently, that the inferior
(^plain^) is supported by the lower Vvater PQNO. 
The reason is, because the lower VVater presseth up with 
the weight of 48 pound. It is in it felt 400 pound: but 
being burdened with 352, it cannot thrust up with more 
weight than 48. Now, it pressing up with 48, must ease 
<P 112>
the beam of 48, and counterpoise so much of the superior
VVater, and consequently the beam must support 
only 352 pound of it. But put the case (you say) the 
weight R, were 130 pound, 160 pound, or 180 pound, 
would the beam be less or more burdened with the superior 
Water? I answer, if R be 130 pound, then the beam 
supports only 132 pound of the superior Water; for if
the inferior be only burdened with 130, the weight of R,
and with two the weight of the inferior (^plain^) , then must
it press up with 368, and by this means, must ease the beam 
of so much, it sustaining 132 pound only, According to 
this compting, when the Lead R weighs 160 pound, the 
beam supports only 238 pound of the superior Water. 
If it weigh 180 pound, it sustains 218. And if the weight 
R were taken away, the beam supports no more of the 
superior VVater than two pound. 
   To proceed a little further; imagine the two (^Plains^) to
be drawn up 17 foot nearer the first surface IK, namely as
high as ZW. This done, the union breaks up, and they 
presently fall asunder. The reason is, because the surface
ZW is not able to support 352 pound, but only 300, 
which I prove thus. If 68 foot sustain 400, then 51
foot must sustain 300. I say 68, and not 34, because as 
was noted, the Pressure of the Air upon the surface IK,
is equivalent to other 34 foot: and therefore though 
the deepness of this VVater, between IK, and LM be but 
34 foot really, yet it is 68 foot virtually, and in effect, 
Imagine sencondly the surface IK to subside 17 foot, namely
to ZW. In this case the union is broken also, and the 
lower (^Plain^) falls from the upper. The reason of this, is
the same with the former; because by what proportion 
you diminish the hight of the superior VVater, by that 
<P 113>
same proportion you diminish the upward. Pressure of the
lower VVater. Therefore, if you subtract from the superior 
VVater 17 foot, that weighs 100 pound, you subtract 
likewise 100 pound from the inferior VVater, and 
consequently, you make it press up only with 300, but 
300 is not able to counterpoise 352. 
   Let us suppose thirdly, the superior (^Plain^) , and the     #
superior
Water to be annihilated; then I say, the Pressure 
and force of the under Water would thrust up the inferior
(^Plain^) and the weight R about eight foot higher then XY
and there suspend them. The reason is, because the surface
XY, being able to sustain 400, and being burdened 
only with 352, must have the weight of 48. Now 
the upper (^Plain^) being taken away, and the upper Water 
also, and the empty space of both remaining, the said
weight of 48 pound, must carry the under (^Plain^) as high as
is said. Let us suppose fourthly, the Pressure of the Element 
of Air, that rests upon IK, to be taken away, then 
must the two (^Plain^) bodies be disunited, the inferior        #
falling
from the superior. The reason is, because in this case, 
the superior Water would have but the weight of 200 
pound, and consequently the inferior, would press up only 
with as much: but 200 is not able to counterpoise 352. 
   From what is said we see first, that in all Fluids there is
an upward Pressure, as well as a downward; and that the 
one is alwayes of equal force to the other: because the         #
inferior
(^Plain^) is pressed up with as great force, as the superior
(^Plain^) is pressed down with. We see secondly, that 
in Fluids, there is a (^Pondus^) and a (^Potentia^) . The       #
(^Potentia^)
here is the inferior Water, and the (^Pondus^) is the superior.
Or, the 350 pound of Lead R, may be called the 
(^Pondus^) , which counterpoiseth the (^Potentia^) of the       #
surface 
<P 114>
of VVater XY. We see thirdly, that though the Pressure
of a Fluid, be not the same thing with the natural
weight, yet it is equivalent to it: because the 352  pound 
of Lead R, is sustained by the Pressure of the inferior
VVater, which could not be, unless they were virtually 
the same. We see fourthly, that there may be as much 
Pressure in one foot of Water, as there is weight in 100, or 
in 1000 foot, or in 1000 fathom, For put the case, these 
two plain bodies were suspended, 100 fathom below the 
surface of the sea, and within a foot or two of the ground,
as much weight would be required to pull them asunder, as is 
the weight of a Pillar of Water 100 fathom high, and 4
inches thick every way, which will be more then 3000  
pound weight, besides the weight of the Air above, that
will weigh 200 pound. This could not be, unless there
were as much Pressure in the lowest foot of this Water,
that's 100 fathom deep, as there is weight in the whole 
Pillar above. We see fifthly, the more the (^potentia^) of a
surface is burdened, the more sensible is the (^pondus^)
because the heavier you make the Lead R, that burdens 
the inferior Water, the more weight of the superior Water 
rests upon the Beam. We see sixtly, the more (^unequally^)
a body is pressed, the more the Pressure is (^sensible^) .
For understanding this, consider that the under-face of the 
superior (^Plain^) , is more and less pressed, according to the
more and less weight the Lead R is of: for put the case,
the inferior (^Plain^) were taken away, the face of the         #
superior
(^Plain^) , would be equally prest with the back of it. But 
when the inferior (^Plain^) is united to it, the Pressure of    #
the
Water is kept off; by which means the back is prest more
than the face. Now, as the inferior (^Plain^) becomes heavier
and heavier, by making the weight R more and more 
<P 115>
weighty, the less and less is the face of the superior          #
(^Plain^)
prest up. Hence it is, that as this inequality of Pressure
becomes greater and greater; so the weight of the superior
Water, affects the Beam more and more. Or, if the 
superior (^Plain^) were a sensible body, as (^Animals^) are, it
would find the back of it more and more burdened, according
as the weight R, becomes heavier and heavier. We 
see seventhly, that Water weighs in Water: because all 
the weight the Beam supports, is the burden of the superior
VVater, and not the burden of the inferior (^Plain^) , or
of the weight R. It supports the weight also of the superior
(^Plain^) , but this is not considerable. This is only to be 
understood, when the Pressure in unequal; for if the upper
(^Plain^) were as much prest up, as it's prest down, the 
weight of the superior VVater would not be found by the 
(^Beam^) . We see eighthly, that the higher a surface be, it
is the weaker; and the lower it be, it is the stronger:         #
because 
when the two plain bodies are pulled up, 17 foot, they 
fall asunder. We see ninthly the vanity of the common 
opinion, that maintains two plain (^bodies^) to cleave clos     #
together 
for fear of (^vacuity^) ; and that neither (^Humane^) nor 
(^Angelick^) strength is able to break this union, without the 
rupture and fracture of them both. 
   It may be enquired, upon supposition, that the inferior
(^plain^) had four holes cut thorow the middle, square wise,
as ABCD in the 18 Figure, what (^Phenomena^) would 
follow? Before I answer, consider that this Figure represents
the inner face of the Brass-plate CDNO, of the 
17 Figure, which as was supposed, is four inches from side
to side, and consequently contains 16 square inches. Now, 
imagine the under (^plain^) CDNO, while it is united to 
the uppermost, to have four square inches cutted out of it,
<P 116>
as ABCD. These things being rightly conceived, and 
understood, I say, when the said holes are cutted thorow, 
the beam TV, that now sustains 350 pound, shall by this 
means, only sustain 250 pound. To make this evident,
consider that the under (^plain^) (as was said) contains 16 
square inches. Next, that the top of the inferior Water 
upon which the (^plain^) rests, contains as many, and that      #
every 
inch of the Water weighs 25 pound, seing the whole, as 
was supposed before, weighs 400 pound. Now, I say, the
beam must support only 250 pound of the Water IKLM;
because, these holes being made, the top of the inferior 
Water comes through them, and presseth up the face of the 
superior (^plain^) with 100 pound, and so easeth the beam of 
so much. I affirm next, that though the inferior Water 
NOPQ be in it self 400 pound, and consequently able 
to support the inferior (^plain^) , with the weight R, albeit 
they weighed so much, yet the said holes being cut out, 
it is not able to support more burden than 300. The reason 
is, because of 16 parts that did actually bear up before,
there are only 12 now that sustains. And every one
of these twelve, being but able to support 25 pound, it 
necessarily follows, that the greatest weight they are able 
to sustain, is 300 pound. I affirm thirdly, that if a fifth 
hole were cut through, the under (^plain^) would fall from the
upper; because in this case, the inferior Water is not able 
to support 350 pound as before, seing of 16 parts, there
are five wanting, and eleven remaining, cannot support more 
weight than 275 pound. Moe questions of this kind might 
be proposed; as first, what would come to pass, if the 
the upper (^plain^) had as many holes cut through it, answering
to the four of the nether? Secondly, what would follow, 
if the nether (^plain^) were intire, and four bored through 
<P 117>
the upper? But I shall supersede, and leave these to be 
gathered by the judicious Reader. 
   From this Experiment we see first, that the broader and 
larger a surface of a Fluid be, it's the more able to sustain   #
a 
burden, and the narrower it be, 'tis the less able. Secondly, 
that each part of a surface, is able to sustain so much 
weight, and no more, and no less. 
   Before I put a close to this Experiment, it will be needful
to answer an objection, proposed by (^Doctor More^) in his 
(^Antidote against Atheism^) , against the Pressure of the Air,
which in effect militats, by parity of reason, against the 
Pressure of the VVater likewise. He argues thus. If the 
Air wer indowed with so much Pressure, as is commonly 
affirmed, then it ought to compress, squeez, or strain          #
together, 
any soft body that it environs, as (^v.g. Butter^) . Put 
the case then, there were a piece of (^Butter^) , four inches   #
broad 
every way, and one inch thick, containing 16 square 
inches, upon every side; as may be represented by the 
Figure 19. In this case, there is a far greater Pressure, 
upon the two faces, than upon the four edges, and therefore,
it ought to be comprest, and strained together, to 
the thinness of a sheet of Paper. For answer, let us suppose
the piece of (^Butter^) , to be 30 or 40 foot below the 
surface of a Water, where it ought to suffer far more           #
Pressure, 
than above in the Air. Next, that it lies (^Horizontal^) ,
with one face upward, and the other downward.
Thirdly, that the upper face supports a Pillar of Water 
200 pound weight, and consequently, that the under face 
is prest up with as much. And lastly, that every edge is 
burdened with 50. It may be represented, with the help
of the fancy, in the 19 Figure, where AB is a piece of 
(^Butter^) four inches square, and one inch thick. Only take 
<P 118>
notice, that nothing here is represented to the sight, save 
one of the four edges, namely AB; the other three, and 
the two faces being left to the fancy: Yet, the upper face 
may be represented by FHKM, and the under by NOPQ.
These things being rightly understood, it is wondered,
why the two great and heavy Pillars of Water, the 
one EGILFHKM, that presseth downward, and the 
other NOPQRSTV, that presseth upward, do not 
strain together the sides of the (^Butter^) ; seing the         #
Pressure
of the Water BC, and the Pressure of the Water 
DA, are far inferior to them for strength, even by as 
much difference, as four exceeds one. Though this objection 
seem somewhat, yet it is really nothing, which 
I make evident after this manner. First, I grant that 
the upper face FHKM is burdened, with 200 pound, 
and the nether face NOPQ with as much. Secondly, 
that the edge B, is only burdened, with 50 pound, as is the 
edge A. The other two edges, sustains each one, as 
much. Secondly, though this be, yet I affirm the two 
sides to be no more burdened, than the edges: that's
to say, the Pressure upon the sides, is equal to the Pressure
upon the edges, which I prove thus. The Pressure 
upon the part M, is equal to the Pressure upon the part K, 
but the Pressure upon the edge B, is equal to the Pressure 
upon the part M: therefore the Pressure upon B, is equal 
to the Pressure upon K. The major Proposition is evident, 
because the Pillar of Water LM, is not of the same weight, 
with the Pillar of Water IK. The Minor is also evident,
because, the Pillar BC, is of the same weight, with the 
Pillar LM. Now, if the Pressure upon the edge B, be 
equal to the Pressure upon M and K, it must be likewise 
equal to the Pressure upon H and F. If this be, then the 
<P 119>
edge of the (^Butter^) B, must be no more prest, than the side
FHKM: therefore the Water BC, can no more yeeld 
to the VVater  EFGHIKLM, and suffer the (^Butter^) to
be squeezed out at B, than the VVater LM, can yeeld to 
the VVater EFGHIK, and suffer the (^Butter^) to be 
squeezed out at M. If any man shall insist and say, that 
the upper face bears the weight of four Pillars, which 
weighs 400 pound; but the edge B is only burdened with 
50: therefore 50 ought to yeeld to 400. I answer, according 
to the 29 Theorem, namely, that a (^thicker^) Pillar 
of a Fluid is not able to press, or move a (^slenderer^) ,      #
unless
there be an unequal Pressure, therefore the thick Pillar, 
that presseth the face, cannot move the slender Pillar, that 
presseth the edge: but there is here no unequal Pressure, 
seing the Water XYZV, is of the same hight with the 
four Pillars that rests upon the face of the (^Butter^) . I     #
grant,
if the said Water were not so high, as the other is, by the 
one half; then surely the (^Butter^) would be squeezed out at 
B; because the shorter a Pillar be, the less Pressure is in     #
the 
surface under it; therefore, there must be less Pressure,       #
according 
to that supposition in the Water BC, then now is. 
Or put the case, the Pillar IK were shorter then GH, or 
LM, the same effect would follow, namely, a squeezing 
out of the (^Butter^) from K. Or, let us suppose the Pillar I 
K, to be higher than GH or LM. In such a case, the 
weight of the said Pillar would press through the (^Butter^) .
   From what is said, we shall only inferr this conclusion, 
that equality of height between Pillars of a Fluid makes equal 
Pressure, and inequality of hight makes unequal Pressure.
Therefore 'tis no matter, whether they be gross or 
small, thick or slender, provided they be all of the 
same Altitude. 

<S SAMPLE 3>
<P 197>
[}AN ACCOMPT OF 
MISCELLANY 
OBSERVATIONS, 
LATELY MADE, BY THE  AUTHOR OF THE 
FOREGOING EXPERIMENTS.}]

[}OBSERVATION I.}]

   In (^May^) 1669, there was need of a new 
Sink, on the east side of (^Tranent^) , for 
winning of (^Coals^) . But while the (^Coalhewers^)
were in digging down, and had 
come the deepness of 13 or 14 fathom, 
they were stopped from working by 
(^Damps^) , or ill Air, that flowed out plentifully from the 
sides of the sink, wherein there were a great number of 
(^Cutters^) , or rifts, out of which that ill Air came. To try 
the nature and power of (^Damps^) , I took a dog, and fastned 
him in a (^bucket^) , with a small roap, that he might not leap
over, and when he had gone down 7 or 8 fathom, he presently
begins to howl, and cry pitifully, as if he had been 
<P 198>
beaten fore with a rod, and a little after, he begins to        #
stagger, 
and his feet failing him, he falls down, as one overtaken 
with the Epilepsy, and in going downn to the bottom, his 
eyes turning in his head, they appeared very shining and 
clear like two large bright Diamonds. Fearing, that the 
(^Damp^) should have killed him out of hand, he was instantly
pulled up from the bottom, where he had not tarried 15          #
(^seconds^)
of time. And when the bucket had come to the mouth 
of the (^sink^) , he was pulled out, and laid upon the ground,  #
to 
get fresh Air. When he had lien a while as dead, he begins 
at last to gape, and gasp, and make some respirations, as if    #
he 
had been rather expiring, than recovering. Next, he began to 
stir and move his feet, and after, to raise him self upon his 
knees, his head staggering and wavering from side to side.
After a (^minut^) or two, he was able to stand upon his feet, 
but so weakly, that he was not in capacity to walk or run.
Yet at last, being much refreshed, he escaped from us, and ran 
home, but slowly. In the afternoon, the same Experiment 
was repeated, with another dog, whose case was the same 
in all things. But after he was perfectly recovered, for a 
further trial, we let him down the second time, and suffered 
him to tarry in the bottom of the (^sink^) , about the space
of three minuts: but when he was pulled up, and taken 
out, we found no symptomes of life in him; and so after 
half an hour and more, his body began to swell, which           #
ordinarily
befalls such, who are killed after this manner. After
this, we sent down in the Bucket, a little Chicken, 
which, when it came near the (^Damp^) , presently flapped 
with the wings, and falling down, turned over and over 
for a pretty while, as if it had been taken with a              #
(^vertigo^) , or 
giddiness. But by drawing up the Bucket in halfe, and 
bringing the Bird to the fresh Air, it recovered. In the 
<P 199>
evening, we let down a (^lighted Candle^) , but it was soon
extinguished, when it came near mid-sink; for here, rather 
than in the bottom, was the strongest Damp. Lastly, 
we let down by a chord, a (^Brand-iron^) , with burning 
Coals, whose flame was soon put out, and after a little 
while, we perceived the red Coals to be extinguished by 
degrees; yet not totally, because, as the Coal-hewers observed,
the power of the (^Damp^) was not so strong, as before. 
These (^Damps^) then have their ebbings and flowings, which 
seem to depend upon the weather, or rather upon the situation 
of the winds, and their force. For 'tis observed, that a 
high South-west wind causeth ill Air in this place; and 
that, by reason of much wast ground, that lies upon the 
South, and South-west hand of this (^Sink^) , whence are        #
conveyed
under ground by secret passages, which are nothing 
else but so many rifts and openings, commonly called by 
the (^Coal-hewers^) , (^Gutters^) , corrupted and rotten Air,   #
full 
of sulphurious stems. The reason why these passages are 
open, and replenished with nothing, but corrupted Air, is 
this, the Water, that's ordinarily called the Blood of the 
Coal, being withdrawn with subterraneous Gutters (commonly
called (^Levels^) ) that are digged, and wrought under 
ground, sometimes a very long way, for drying of the            #
(^Mines^) ,
and the veins of the earth being now empty, there succeeds
Air; which Air, by process of time, and long standing, 
rots, and contracts a sulphurious quality, which 
causeth sudden death. Now, when the wind is high, and 
strong from the South or South-west, that sulphurious Air 
is driven through the ground, and coming to (^Sinks^) and 
(^Mines^) , where men are working, presently infects the place,
and hinders the work. 'Tis often observed, that the wind 
and Air under ground, keep a correspondence in their motion, 
<P 200>
with the wind above ground: and therefore, when the 
wind is in such a point above, 'tis found, that the motion 
of the Air below runs such a way, and the contrary way, 
when the wind above ground, is in the opposite point.
When there is a free passage between the bottom of the 
two Sinks, you may observe the wind come downn through 
the one, and running alongst under the ground, rise up thorow
the other, even as Water runs thorow a (^Siphon^) . For 
this cause, when the (^Coal-hewers^) have done with such a 
(^Sink^) , they do not use to stop it, or close it up, but      #
leaves
it standing open, that the Air under ground may be kept 
under a perpetual motion and stirring, which to them is a 
great advantage. 'Tis very strange to see sometimes, how 
much Air, and how fresh it will be, even at a very great 
distance, namely four or five hundred pace, from the mouth 
of the (^Sink^) . This could never be, unless there were a      #
considerable
Pressure and weight in it, whereby it is driven forward,
thorow so many (^Labyrinths^) . And even in the utmost 
room, where the (^Coal-hewers^) are working, the Pressure is as
great, as it is above ground, which is found by the             #
(^Torricellian
Experiment^) . In such a case, the Air cannot press down 
thorow the Earth and Metalls, therefore the Mercury must 
be suspended, not by a Pillar from the (^Atmosphere^) , but by
the (^Bensil^) of it. Nay, put the case, that the whole Element
of Air were destroyed, and this remaining, yet would it be 
able to support 29 inches. To shut up this discourse, it is     #
observed
by the (^Coal-hewers^) , that when there is ill Air in a 
(^Sink^) , a man may perceive distinctly, what is lying in the  #
bottom, 
so clear and transparent is the Air of it: but when the 
(^Damp^) is gone, the (^Medium^) is not so clear. In temperat   #
and 
cold weather, the (^Damps^) are not so frequent. From this      #
(^Sink^) ,
in soft winds, or in Northerly winds, or when it blows from 
East or North-east, the (^Damps^) are driven away. 
<P 201>
[}OBSERVATION II.}]

   (^Jupiter^) upon Wednesday night, at eleven a clock, 
being 24 of (^November^) , 1669, had the following 
position with the stars of (^Gemini^) . He was so near to the
Star C, that to appearance, the points of his rayes did 
touch it. This Star by looking upon the material Glob, 
is fixed in the very (^Zodiack^) , and in the 13 degree of 
(^Cancer^) , and is the very navel of the following (^Twine^) . #
The
Star A is (^Castor^) . The Star B is (^Pollux^) . The star D,   #
is
fixed in the forefoot of the following (^Twine^) . From this 
place he moved, with a retrograde motion, till he came 
to the 5 of (^Cancer^) , about the 20 of (^February^) , 1670, 
and from that time became (^Direct^) in his motion, and so 
upon the 27 of (^March^) , 1670 at 9 a clock, he was in a 
right line with (^Canis minor^) , and the brightest Star in 
(^Auriga^) , and was in a right line with the eastmost shoulder
of (^Orion^) , and (^Castor^) in (^Gemini^) , or with that      #
Star, when 
South-west, that's highest, and West-most.

<S SAMPLE 4>
<P 207>
[}OBSERVATION IV.}]

   Upon (^Tuesday^) the 19. of (^July^) 1670, the following 
Experiment was made. In the middle Marches between 
(^Scotland^) and (^England^) , there is a long tract of Hills,
that run from (^Flowdon^) , many miles South and South-west, 
amongst the which, the Mountain (^Cheviot^) is famous beyound,
and conspicuous above all the rest for altitude, from
whose top a man may discern with one turning of his eye, 
the whole Sea-coast from (^New-castle^) to (^Berwick^) , much   #
of
(^Northumberland^) , and very many Leagues into the great 
(^German Ocean^) : the whole (^Mers^) and (^Teviotdale^) , from
the foot of (^Tweed^) , to very near the head of it.            #
(^Lauderdale^) , 
and (^Lammer-moor^) , and (^Pentland-hills^) above              #
(^Edinburgh^) .
The North side of this Mountain is pretty steep, yet easie 
to climb, either with men or horse. The top is spacious, 
large and broad, and all covered with a (^Flow-moss^) , which 
runs very many miles South. When a man rides over it, 
it rises and falls. 'Tis easie to thrust a Lance over the head 
in it. The sides if this Hill abounds with excellent            #
Wellsprings,
which are the original of several Torrents, amongst 
the which (^Colledge-Water^) is famous, upon which, not a 
mile from the foot of this Mountain is (^White-hall^) . The
adjacent Hills are for the most part green, and excellent 
for the pasturage of Cattel. Not many years ago, the 
whole Valleys near the foot of (^Cheviot^) , were Forrests      #
abounding 
with (^Wild-Deer^) . 
   Upon the highest part of this Mountain was erected the 
(^Torricellian Experiment^) for weighing of the Air, where 
we found the altitude of the (^Mercurial Cylinder^) 27 inches
and an half. The  Air was dry and clear, and no wind. In 
our Valley-Countreys, near to the Sea-Coast, in such
<P 208>
Weather, we find the altitude 29 inches and an half.
When this difference was found, care was taken to seal up
closly with (^Bee-wax^) , mixed with (^Turpentine^) , the       #
orifice
of the Vessel, that contained the stagnant Mercury, and 
thorow which the end of the Pipe went down. This being 
done with as great exactness as could be, it was carried to 
the foot of the Mountain in a Frame of Wood, made on
purpose, and there opening the mouth of the Vessel, we 
found the Mercury to rise an inch and a quarter higher than 
it was. The reason of this strange (^Phenomenon^) must be this,
namely a greater Pressure of the Air at the foot of the Hill, 
than upon the top: even as there is a greater Pressure of 
Water in a surface 40 fathom deep, than in a surface 20 
fathom deep. 'Tis not to be doubted, but if the root of 
the Mountain had been as low as the Sea Coast, or as the 
surface of (^Tweed^) at (^Kelso^) , the (^Mercurial Cylinder^)  #
would
have been higher. This way of observing, seems to be 
better than the common: for while the (^Baroscope^) is carried 
up and down the Hill, without stopping the orifice of 
the Vessel, that contains the stagnant Mercury, the             #
(^Cylinder^)
makes such reciprocations, by the agitation of a mans 
body, that sometimes abundance of Air is seen to ascend 
up thorow the Pipe, which in effect makes the (^Cylinder^)
shorter than it ought to be. But if so be, the end of the 
Pipe be immerged among (^Quick-silver^) , contained in a 
Glass with a narrow orifice, so that it may be stopped          #
compleatly,
you will find no reciprocations at all. And to 
make all things the more sure, the Glass may be filled up
either with (^Mercury^) , or with Water above the (^Mercury^) ;
by which means the (^Cylinder^) in the down-coming, or in the 
up-going shall remain immoveable. Besides the stopping 
of the orifice of the said Glass, you may have a wider          #
Vessel, 
<P 209>
that may receive the same Glass into it, and it being 
full of Water, may so cover the sealed orifice, that there 
shall be no hazard of any Air coming in. Or this Experiment
may be first tried at the root of the Hill, and having 
stopped compleatly the mouth of the Vessel, the whole 
Engine may bee carried up to the top, where you will find 
the (^Mercury^) subside and fall down so much; namely after 
the said orifice is opened: for as the stopping of the orifice
at the root of the Hill, is the cause, why that same degree 
of Pressure remains in the stagnant Liquor; so the opening 
of it upon the top of the Hill, is the cause why it becomes
less. 
   This Experiment lets us see, that the Pressure of the 
Air seems to be as the Pressure of the Water, namely the 
further down the greater; and the further up the less; and 
therefore, as by coming up to the top of the Water, there 
is no more Pressure, so by coming up to the top of the Air, 
there is no more weight in it; which in effect sayes, that 
the Air hath a determinant hight, as the Water hath. From 
this Experiment we cannot learn the determinant hight of 
the Air, because the definit hight of the Mountain is not 
known. I know there are some, who think that the Air 
is indefinitly extended, as if forsooth, the Firmament of 
fixed Stars were the limits of it, but I suppose it is hard to 
make it out. 

[}OBSERVATION V.}]

   (^June^) 5. 1670. I observed the (^Sun^) within 3 (^minuts^) #
of 
setting, to have a perfect (^oval figure^) , the two ends lying
level with the Horizon. His colour was not red as 
ordinarily, but bright and clear, as if he had been in the 
<P 210> 
(^Meridian^) : neither was the Sky red, but clear also. And by 
the help of the (^Pendulum^) Clock, I have observed his body 
to be longer in setting than it ought, by eight (^minuts^) ,    #
and
sometimes by (^ten^) , and his Diameter longer in going out of 
sight than it ought, by two, and sometimes by three             #
(^minuts^) . 
The reason of these (^Phenomena^) , must be the (^Refraction^)
unquestionably. 

[}OBSERVATION VI.}]

   Upon (^Saturday^) evening the 30 of (^July^) 1670, and the 
night following, till about two a Cloak in the (^Sabbath^)
morning, there fell out a considerable rain, with great 
thunder, and many lightnings. About (^Sun-set^) , the           #
convocation 
of black clouds appeared first towards the (^Horizon^)
in the South-west, with several lightnings; and the 
wind blowing from that point, carried the clouds and rain
over (^Mid^) and (^East-Lothian^) , towards the (^Firth^) and   #
(^Seacoast^) .
About 9 a clock, the whole Heavens almost were 
covered with dark clouds, yet the rain was not very great, 
neither were the (^thunder claps^) frequent, but every          #
(^fifth^) or 
(^sixth second^) of time, a large and great lightning brake     #
out.
But before the (^thunder crack^) was heard, which happened
every fourth of fifth (^minut^) , the lightning was so terrible
for greatness, and brightness, that it might have bred          #
astonishment.
And because the night was very dark, and the 
lightning very splendid, a man might have perceived 
houses and corn-fields at a great distance. And if any had 
resolved to catch it, in the breaking out, it did so dazle 
the eyes, that for half a (^minut^) , he was not able to see    #
any 
thing about him.
   Sometimes the lightning that went before the thunder,
<P 211>
brake forth from the clouds, like a long spout of fire, or 
rather like a long flame raised high, with a Smiths Bellows, 
but did not continue long in sight. Such an one 
above the Firth was seen to spout downward upon the Sea.
Sometimes there appeared from the one end of the cloud 
to the other, an (^hiatus^) , or wide opening, all full of      #
fire,
in form of a long furrow, or branch of a River, not straight, 
but crooked. I suppose the breadth of it, in it self, would 
have been twenty pace and more, and the length of it five 
or six hundred pace: the duration of it, would have been 
about a second of time. Sometimes a man might have perceived
the nether side of the cloud, before the crack came, 
all speckled with streams of fire, here and there, like the 
side of an Hill, where Moor-burn is, which bake forth 
into a lightning. But there was one, after which followed 
a terrible thunder crack, which far exceeded all the rest, 
for quantity and splendor. It brake out  from the cloud, being
shot from North to South, in form of fire from a great 
(^Cannon^) , but in so great quantity, as if a Gun ten foot     #
wide, 
with 500 pound weight of Powder in it, had been fired. And 
surely the lightning behoved to be far greater in it self,      #
seeing
it appeared so great, at so great a distance. It did not 
evanish in an instant, like the fire of a Gun, but continued 
about a second and an half; by reason (it seems) that it 
could not break out all at once. This did so dazle the fight,
that for half a minut almost, nothing was seen, but like a 
white mist flying before the eyes. The whole Countrey 
about was seen distinctly. 
   All these great lightnings were seen a considerable time, 
before the crack was heard. Sometimes 30 (^seconds^) numbered
by the (^Pendulum Clock^) interveened, namely when 
the thunder was at a distance, about 7 or 8 miles. Sometimes
<P 212>
15 or 16 only interveened. But when the thunder 
was just above our head, no more passed, than 7 or 8,
which seems to demonstrat, that these thick black clouds, 
out of which the thunder breaks, are not a (^Scottish^) mile
from the earth, when they are directly above us. 
   'Tis observable, that in all lightnings, and thunderings,
there is no smoke to be seen, which seems to evince, that 
the matter whereof they generated, must be most pure, 
and subtil. Who knows, but this Countrey, that abounds 
with (^Coal^) , may occasion more thunder and lightnings, than
other places, namely be sending up sulphurious exhalations
to the middle region of the Air, wherewith the (^Coalmines^)
abound. 

[}OBSERVATION VII.}]

   This is a method for finding out the true South and 
North Points, which are in effect very difficult to 
know. Take therefore four pieces of Timber, each one 
of them five foot long, and about six inches thick, squarewise.
Sharpen their ends, and fix them so in the ground, 
that they may stand Perpendicular, and as near to South and 
North, by a (^Magnetick Needle^) , as may be. The place 
would be free of Trees, or of any such impediment, that it 
may have a free prospect of the Heavens. As for their 
distance one from another, let the two North-most, and 
the South-most be two foot asunder: let the two East-most, 
and two West-most, be but one foot, making as 
they stand, an (^oblong quadrangle^) . For keeping them         #
equidistant
above, as well as below, take four bars of Wood, 
about three inches broad, and one inch thick, and nail them 
round about upon the four sides, on each side one, so that 
<P 213>
being nailed on (^Horizontally^) , they may make (^right        #
angles^) ,
with the tops of the standards above. There are then for 
distinctions cause, the North-bar, and the South-bar, 
that runs East and West, and the East-bar, and the West-bar,
that runs South and North. There is here no difficulty 
in the thing it self, but only in the fancy to conceive
it. Besides these four, there must be other four of the 
same form and fashion, nailed on farder down about the 
middle of the four standards. Take next some small Brass 
Wyre strings, such as are used in (^Virginals^) , and fix one   #
from 
the middle of the South-bar, that's upmost, to the middle 
of the South-bar just under it. Fix it so, that it may be 
exactly Perpendicular, which may be done, with a great 
weight of Lead. Take a second Wyre string, and hang it 
plumb from the West end of the North-bar, and another 
from the East end of the same Bar, I mean the Bar that's 
nearest to the top. These three strings so fixed, will go 
near to make an (^equilateral triangle^) . 
   Now because the device is for finding out the (^Meridian^)
by the Stars in the night time, not by any indifferently,
but by these that are nearest to the (^Pole^) , therefore       #
observe
in (^July^) and (^August^) , when the (^Guard-stars^) in the    #
evening 
begin to come down towards the West, and keeping closs
one eye, bring the other somewhat near to the South-most 
string, and order your sight so, that this string, and 
the West-most string upon the North side, may catch the 
foremost (^Guard-star^) in the down-coming, when it is furthest
West, and there fix it. When the same Star is turning 
up towards the  East, catch it by the South-most string,
and the East-most string on the North side, and your work 
is done, if so be, you divide exactly, between the East-most
and West-most, and there hang a fourth string, which 
<P 214>
with the string upon the South-side, gives you the true 
South and North. For better understanding, note first,
that, when the (^Guard-stars^) are coming down, or going up, 
the (^Altitude^) varies quickly, but the (^Azimuth^) , or       #
motion
from East to West, will not vary sometimes sensibly in two 
hours almost, which is a great advantage in this case. But 
when you find out the (^Meridian^) with a (^Plain^) , and a     #
Perpendicular
(^Stilus^) , by the shadow of the Sun, if it be not when 
he is about East and West, the (^Azimuth^) alters more than 
the (^Altitude^) , which is a great disadvantage. Now its 
certain, the slower the motion be from East to West of any 
Star, it is the easier to observe, and it is the more sure
way. Note secondly, that special care must be had, to 
cause the strings hang Perpendicular. Note thirdly, that 
before you beg in your Observations, the South-most string 
must be made immoveable, but the East-most, and West-most, 
on the other side, must not be so, because as the 
Stars in going about move from East to West, so must the 
said two strings be left at at liberty, to move a little        #
hither 
and thither, till Observations be ended. Note fourthly,
that assoon as you perceive sensibly, the foremost              #
(^Guard-star^)
to decline towards the West, then you must begin to 
observe, which is nothing else, but to fix your eye so, 
that the South-most and West-most string, may cover the 
said Star. And because in coming down, it goes West, 
therefore, let the West-most string move towards the left 
hand by degrees, following the Star to its utmost, till it 
be covered by them both. Follow the same method, in 
observing the same Star in going up towards the East. Note 
fifthly, that when you make the two strings cover the Star, 
that which is nearest to the eye, will appear transparent, 
and of a larger size, so that you may perceive distinctly 
<P 215>
thorow it, not only the Star it self, but the other string      #
also, 
which is a great advantage. This is evident to any, 
who holds a bended silk threed between their eye and a 
Star in the night time; for when you direct your sight to 
the Star, the string appears like the small string of a         #
(^Virginal^)
when it trembles. Note sixthly, that in observing 
in a dark night, you must have a (^Cut-throat^) , that by the
light of the candle you may perceive the strings. Some 
other things might be noted, but you will find them better 
by experience, than they can exprest here. 
   I named (^July^) and (^August^) in the evening for observing
the (^Guard-stars^) , when they are West-most, but there are 
several other seasons, when this may be done as conveniently.
They are East-most in the latter end of (^October^) , and 
beginning of (^November^) about 5 or 6 a clock in the morning. 
If a man were desirous to make this observation quickly, I 
suppose he might in the end of (^October^) , find the said      #
stars
West-most in the evening, and East-most the next morning. 
Besides the (^Guard-stars^) , a man may make use of the         #
(^Polar-star^) ;
for as it goes higher, and lower than the true (^Pole^) , by 
2 degrees and 26 minuts, so it goes as much to the East, 
and as much to the West, once in 24 hours. In the end 
of (^July^) , you will find the (^Polar-star^) East-most, about #
9 
a clock at night, and in the end of (^January^) West-most at 9 
a clock. Note, that every month, the fixed stars come 
sooner to the same place by two hours: therefore in the 
end of (^August^) the (^Polar-star^) must be West, at 7 a clock #
at 
night, and East at 7 a clock in the morning. When the 
(^Meridian^) is found out after this manner, there is no        #
(^Star^) or 
(^Planet^) can pass it, but you may know exactly when, be it 
never so high, or never so low. For there is nothing to 
be done, but to wait, till the South-most and North-most 
<P 216>
string cover the body of the (^Star^) . If it be the Sun, 
hold up a white Paper, behind the two strings, and  when 
their shadows do co-incide, and are united, then is his 
Center in the (^Meridian^) . If the Sun do not shine clear, as
when he is under mist, or a thin cloud, you may exactly 
take him up in the (^Meridian^) , with the two strings. This 
Frame will serve as well, to know when any of the North 
Stars comes South, or North, and consequently when they 
are highest, and when they are lowest: for being fixed in 
an open place of the (^Orchard^) , there's no (^Celestial       #
Body^) can 
pass the (^Meridian^) , either on the one side, or the other,   #
but 
it may be catched, what ever the Altitude be, and that 
most easily. 

[}OBSERVATION VIII.}]

   There hath been much inquiry made by some anent
the reason, why the dead body of a man or beast, 
riseth from the ground of a Water, after it hath been there 
three of four days. But though many have endeavoured to 
solve the question, yet the difficulty remains; and in effect 
it cannot be answered, without the knowledge of the foregoing 
Doctrine, anent the nature of fluid Bodies. To 
find out the reason then of this (^Phenomenon^) , consider,     #
that
all Bodies, are either naturally heavier then Water, as 
Stone and Lead, or naturally lighter, as Wood and Timber. 
If they be heavier, they sink: if they be lighter, 
they swim. Now I say, a mans body immediatly after 
he is drowned, his belly being full of Water, must go to
the ground, because in this case, it will be found              #
(^specifically^)
or (^naturally^) heavier then Water. That's to say, a 
mans body, will be heavier, than as much Water, as is 
<P 217>
the bulk of a mans body. For pleasing the fancy, imagine 
a Statue to be composed of Water, with all the true dimensions
of the person that's dead, so that the one shall 
answer most exactly to all the dimensions of the other. In 
this case, if you counterpoise them in a Ballance, the real 
body, that's made up of flesh, blood, and bones, shall 
weigh down the other. But after this dead body hath lien 
a short time among the Water, it presently begins to swell, 
which is caused by the fermentation of the humors of the 
blood, which goeth before putrefaction, and after three or 
four dayes swells so great, that in effect, it becomes          #
naturally 
lighter than Water, and therefore riseth. That is 
to say, take that body, that is now swelled, and as much 
bulk of Water, as will be the precise quantity of it, and 
having counterpoised them in a Ballance, you will find the 
Water heavier than the body. 

<S SAMPLE 5>
<P 224>
[}OBSERVATION XI.}]

   Take a slender chord, about 4 or 5 yards in length, 
and fasten the middle of it to the seiling of a Room 
with a nail, so that the two ends of it may hang down equally.
Take next a piece of Wood, two or three foot long, 
two inches broad, and one inch thick, and boring an hole 
in each end of it, put through the two ends of the chord, 
and fasten them with knots; but so, that the piece of 
Wood may ly Horizontal, and be in a manner a (^Pendulum^)
to swing from the one end of the Chamber to the other.
Take next a Bullet of Lead or Iron, about 20 or 24 
ounces, and lay it upon the said piece of Wood: but because 
it cannot well ly, without falling off, therefore nail 
upon the ends, and the sides of the Timber, four pieces of 
Sticks, on each end one, and on each side one, as (^Ledgets^) ,
for keeping the Bullet from falling off. All things being 
thus ordered, draw up the piece of Wood towards the one 
side of the Room, by which means losing its horizontal 
position, it will ly declining-wise, like the roof of an        #
house. 
In this position, lay the Iron Bullet in the upmost end of 
it, and then let them both pass from your fingers, the one 
end of the Wod going foremost, and you will find it swing 
towards the other side of the house, and return again, as a 
(^Pendulum^) . This motion, if the Wood be well guided in 
its vibrations, will last perpetually, because in its moving 
down, the Bullet is hurled from the one end of the Wood, 
to the other, and hits it so smartly, that it begets in it, 
<P 225>
an impulse, whereby it is carried farder up, than it would 
be, without it. By this means, the (^vibrations^) get not       #
liberty
to diminish, but all of them are kept of the same 
length. In the second vibration, the same Bullet is hurled
back again to the other end, and hiting it with all its
weight, creats a second impulse, wherewith the Wood is 
carried, as far up as the point it was first demitted from. 
   Though this may seem a pretty device to please the 
fancy, that's many times deceived, while things are presented 
to it, by way of speculation, yet upon tryal and experience,
there will be found, an unspeakeable difficulty: 
and it's such an one, that a man would not readily think 
upon. I said, that when the Wood was let go, and was 
in passing down, the Bullet in it, would hurl down, and 
hit the opposite end, and beget an impulse; but there is 
no such thing, for verily, though the Bullet be laid upon 
a very declining plain Board, whereupon no man could 
imagine a round body could ly, yet all the time the Board 
is in swinging, from the one side of the Chamber, to the 
other, and consequently, sometimes under an horizontal, 
and somtimes under an declining position, the Bullet lies 
dead in the place, where you first placed it. This Observation 
is not so much for a perpetual motion, as for finding 
out the reason of this pretty (^Phenomenon^) , namely,
what's the cause, why the Bullet, that cannot ly upon a 
reclining Board, while it's without motion, shall now ly 
upon it, while it's under motion? What is more difficult,
and nice, to ly upon any thing, that declines from a levell, 
than (^Quick-silver^) ; yet lay never so much of it upon this
Board, while it is swinging, it shall ly dead, and without 
motion. But no sooner you stop the motion of the wood,
<P 226>
but assoon, the Bullet, or the (^Quick-silver^) , is hurled,
either this way, or that way.

[}OBSERVATION XII.}]

   I find it mentioned by  some learned persons, that when 
a Ship is under Sail, if a stone be demitted from the top
of the Mast, it will move down in a line parallel with it, and 
fall at the root. Some might think, it ought not to fall 
directly above the place it hang over, but rather some 
distance behind, seing the Ship hath advanced so much
bounds, in the time, wherein the stone is coming down.
Likewise, while a Ship is under Sail, let a man throw up a 
stone never so high, and never so perpendicular, as to his      #
apprehension,
yet it will fall down directly upon his head
again, notwithstanding that the Ship hath run (perhaps) 
her own length in the time, while the stone was ascending 
and descending. This  experiment I find to hold true, 
which may be easily tryed, especially when a man is carried 
in a Boat upon smooth Water, drawn by a horse, as is 
done in some places abroad. Let him therefore throw up 
a little Stone, or any heavy Body, and he will find it descend 
just upon his head, notwithstanding that the Horse 
that draggs the Boat, be under a gallop, and by this means 
hath advanced ten or twelve paces in the time. Or while 
the Boat is thus running, let a man throw a stone towards
the brink of the VVater; in this case he shall not hit the 
place he aimed at, but some other place more forward.
This lets us see, that when a Gun is fired in a Ship under 
Sail, the Bullet cannot hit the place it was directed to. 
Neither can a man riding with a full Career, and shooting
a Pistol, hit the person he aims at, but must surely miss 
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him, notwithstanding, that though in the very instant of 
time wherein he fires, the mouth of the Pistol was most 
justly directed. For remedy wherof, allowance must be 
granted in the aiming at the mark. 
   VVhile a man throws up a stone in a Ship under Sail, it 
it must receive two distinct impulses, one from the hand, 
whereby it is carried upward, the other from the Ship, 
whereby it is carried forward. By this means, the stone in 
going up, and coming down, cannot describe a perpendicular,
but a crooked Line, either a (^Parabola^) , or a Line 
very like unto it. Neither can it describe a perpendicular
Line, in coming down from the top of the Mast, though 
in appearance it seem to do so, but a crooked one, which 
in effect must be the half of that, which it describes in       #
going 
up, and coming down. For this same cause a stone thrown
(^horizontally^) , or towards the brink of the VVater, must 
describe a crooked Line also. And a (^Pistol Bullet^) shot, 
while a man is riding at a full Carreer, must  describe a Line 
of the same kind. Note, that a man walking from the (^Stern^)
of a Ship to the (^Head^) , walks a longer way, than in walking
from the (^Head^) to the (^Stern^) . Secondly, a man may
walk from the (^Head^) to the (^Stern^) , and yet not change    #
his
place. 'Tis observable, that a man (^under board^) , will not 
perceive whether the Ship be sailing, or not, and cannot
know when her (^Head^) goes about. And it is strange, that 
when a man is inclosed in a (^Hogs-head^) , though he have 
light with him, yet let him be never so oft whirled about, 
he shall not know, whether he be going about, or not. 



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