<P_44>

<heading>

OBSERV. VIII . (HOOKE-E3-H,44.3)

OF THE FIERY SPARKS STRUCK FROM A FLINT OR STEEL . (HOOKE-E3-H,44.4)

</heading>

It is a very common Experiment , by striking with a Flint against a
Steel , to make certain fiery and shining Sparks to fly out from
between those two compressing Bodies . (HOOKE-E3-H,44.6)

About eight years since , upon casually reading the Explication of this
odd <font> Phaenomenon </font> , by the most Ingenious <font> Des
Cartes </font> , I had a great desire to be satisfied , what that
Substance was that gave such a shining and bright Light :
(HOOKE-E3-H,44.7)

And to that end I spread a sheet of white Paper , (HOOKE-E3-H,44.8)

and on it , observing the place where several of these Sparks seemed to
vanish , I found certain very small , black , but glistering Spots of a
movable Substance , each of which examining with my <font> Miscrocope
</font> , I found to be a small round <font> Globule </font> ; some of
which , as they looked prety small , so did they from their Surface
yield a very bright and strong reflection on that side which was next
the Light ; (HOOKE-E3-H,44.9)

and each look'd almost like a prety bright Iron-Ball , whose Surface
was prety regular , such as is represented by the Figure A .
(HOOKE-E3-H,44.10)

In this I could perceive the Image of the Window prety well , or of a
Stick , which I moved up and down between the Light and it .
(HOOKE-E3-H,44.11)

Others I found , which were , as to the bulk of the Ball , prety
regularly round , (HOOKE-E3-H,44.12)

but the Surface of them , as it was not very smooth , but rough , and
more irregular , so was the reflection from it more faint and confused
. (HOOKE-E3-H,44.13)

Such were the Surfaces of B. C. D. and E . (HOOKE-E3-H,44.14)

Some of these I found cleft or cracked , as C , others quite broken in
two and hollow , as D. which seemed to be half the hollow shell of a
Granado , broken irregularly in pieces . (HOOKE-E3-H,44.15)

Several others I found of other shapes ; (HOOKE-E3-H,44.16)

but that which is represented by E , I observed to be a very big Spark
of Fire , which went out upon one side of the Flint that I struck fire
withall , to <P_45> which it stuck by the root F , at the end of which
small Stem was fastened-on a <font> Hemisphere </font> , or half a
hollow Ball , with the mouth of it open from the stemwards , so that it
looked much like a Funnel , or an old fashioned Bowl without a foot .
(HOOKE-E3-H,45.17)

This night , making many tryals and observations of this Experiment , I
met , among a multitude of the Globular ones which I had observed , a
couple of Instances , which are very remarkable to the confirmation of
my <font> Hypothesis </font> . (HOOKE-E3-H,45.18)

And the First was of a pretty big Ball fastened on to the end of a
small sliver of Iron , which Compositum seemed to be nothing else but a
long thin chip of Iron , one of whose ends was melted into a small
round Globul ; the other end remaining unmelted and irregular , and
perfectly Iron . (HOOKE-E3-H,45.19)

The Second Instance was not less remarkable then the First ;
(HOOKE-E3-H,45.20)

for I found , when a Spark went out , nothing but a very small thin
long sliver of Iron or Steel , unmelted at either end . So that it
seems , that some of these Sparks are the slivers or chips of the Iron
<font> vitrified </font> , Others are only the slivers melted into
Balls without vitrification , And the third kind are only small slivers
of the Iron , made red-hot with the violence of the stroke given on the
Steel by the Flint . (HOOKE-E3-H,45.21)

He that shall diligently examine the <font> Phaenomena </font> of this
Experiment , will , I doubt not , find cause to believe , that the
reason I have heretofore given of it , is the true and genuine cause of
it , namely , That <font> the Spark appearing so bright in the falling
, is nothing else but a small piece of the Steel or Flint , but most
commonly of the Steel , which by the violence of the stroke is at the
same time sever'd and heatt red-hot , and that sometimes to such a
degree , as to make it melt together into a small Globule of steel ;
(HOOKE-E3-H,45.22)

and sometimes also is that heat so very intense , as further to melt it
and vitrifie it ; (HOOKE-E3-H,45.23)

but many times the heat is so gentle , as to be able to make the sliver
only red hot , which notwithstanding falling upon the tinder </font>
<paren> that is only a very curious small Coal made of the small
threads of Linnen burnt to coals and char'd </paren> <font> it easily
sets it on fire </font> . (HOOKE-E3-H,45.24)

Nor will any part of this <font> Hypothesis </font> seem strange to him
that considers , First , that either hammering , or filing , or
otherwise violently rubbing of Steel , will presently make it so hot as
to be able to burn ones fingers . (HOOKE-E3-H,45.25)

Next , that the whole force of the stroke is exerted upon that small
part where the Flint and Steel first touch : (HOOKE-E3-H,45.26)

For the Bodies being each of them so very hard , the puls $can $not
{TEXT:cannot} be far communicated , (HOOKE-E3-H,45.27)

that is , the parts of each can yield but very little ,
(HOOKE-E3-H,45.28)

and therefore the violence of the concussion will be <font> exerted
</font> on that piece of Steel which is cut off by the Flint .
(HOOKE-E3-H,45.29)

Thirdly , that the filings or small parts of Steel are very apt , as it
were , to take fire , (HOOKE-E3-H,45.30)

and are presently red hot , (HOOKE-E3-H,45.31)

that is , there seems to be a very <font> combustible sulphureous
</font> Body in Iron or Steel , which the Air very readily preys upon ,
as soon as the body is a little violently heated . (HOOKE-E3-H,45.32)

And this is obvious in the filings of Steel or Iron cast through the
flame of a Candle ; (HOOKE-E3-H,45.33)

for even by that sudden transitus of the small chips of Iron , they are
heat red hot , (HOOKE-E3-H,45.34)

and that <font> combustible sulphureous </font> Body is presently
prey'd upon and devoured by the <font> aereal </font> incompassing
<font> Menstruum </font> , whose office in this Particular I have shewn
in the Explication of Charcole . (HOOKE-E3-H,45.35)

<P_46>

And in prosecution of this Experiment , having taken the filings of
Iron and Steel , and with the point of a Knife cast them through the
flame of a Candle , I observed where some conspicuous shining Particles
fell , (HOOKE-E3-H,46.37)

and looking on them with my <font> Microscope </font> , I found them to
be nothing else but such round Globules , as I formerly found the
Sparks struck from the Steel by a stroke to be , only a little bigger ;
(HOOKE-E3-H,46.38)

and shaking together all the filings that had fallen upon the sheet of
Paper underneath , and observing them with the <font> Microscope
</font> , I found a great number of small Globules , such as the former
, though there were also many of the parts that had remained untoucht ,
and rough filings or chips of Iron . So that , it seems , Iron does
contain a very <font> combustible sulphureous </font> Body , which is ,
in all likelihood , one of the causes of this <font> Phaenomenon
</font> , and which may be perhaps very much concerned in the business
of its hardening and tempering : of which somewhat is said in the
Description of <font> Muscovy-glass </font> . So that , these things
considered , we need not trouble our selves to find out what kind of
Pores they are , both-8 in the Flint and Steel , that contain the
<font> Atoms of fire </font> , nor how those <font> Atoms </font> come
to be hindred from running all out , when a dore or passage in their
Pores is made by the concussion : (HOOKE-E3-H,46.39)

nor need we trouble our selves to examine by what <font> Prometheus
</font> the Element of Fire comes to be fetcht down from above the
Regions of the Air , in what Cells or Boxes it is kept , and what
<font> Epimetheus </font> lets it go : Nor to consider what it is that
causes so great a conflux of the atomical Particles of Fire , which are
said to fly to a flaming Body , like Vultures or Eagles to a putrifying
Carcass , and there to make a very great pudder . Since we have nothing
more difficult in this <font> Hypothesis </font> to conceive , first ,
as to the kindling of Tinder , then how a large Iron-bullet , let fall
red or glowing hot upon a heap of Small-coal , should set fire to those
that are next to it first : (HOOKE-E3-H,46.40)

Nor secondly , is this last more difficult to be explicated , then that
a Body , as Silver for Instance , put into a weak <font> Menstruum
</font> , as unrectified Aqua fortis should , when it is put in a great
heat , be there dissolved by it , and not before ; which <font>
Hypothesis </font> is more largely explicated in the Description of
Charcoal . (HOOKE-E3-H,46.41)

To conclude , we see by this Instance , how much Experiments may
conduce to the regulating of <font> Philosophical notions </font> .
(HOOKE-E3-H,46.42)

For if the most Acute <font> Des Cartes </font> had applied himself
experimentally to have examined what substance it was that caused that
shining of the falling Sparks struck from a Flint and a Steel , he
would certainly have a little altered his <font> Hypothesis </font> ,
(HOOKE-E3-H,46.43)

and we should have found , that his Ingenious Principles would have
admitted a very plausible Explication of this <font> Phaenomenon
</font> ; whereas by not examining so far as he might , he has set down
an Explication which Experiment do's contradict . (HOOKE-E3-H,46.44)

But before I leave this Description , I must not forget to take notice
of the Globural form into which each of these is most curiously formed
. (HOOKE-E3-H,46.45)

And this <font> Phaenomenon </font> , as I have elsewhere more largely
shewn , proceeds from a propriety which belongs to all kinds of fluid
Bodies more or less , and is caused by the Incongruity of the Ambient
and included Fluid , which so acts and modulates each other , that they
acquire , as neer as is <P_47> possible , a <font> sperical </font> or
<font> globular </font> form , which propriety and several of the
<font> Phaenomena </font> that proceed from it , I have more fully
explicated in the sixth Observation . (HOOKE-E3-H,47.46)

One Experiment , which does very much illustrate my present Explication
, and is in it self exceeding pretty , I must not pass by :
(HOOKE-E3-H,47.47)

And that is a way of making small <font> Globules </font> or <font>
Balls </font> of Lead , or Tin , as small almost as these of Iron or
Steel , and that exceeding easily and quickly , by turning the filings
or chips of those Metals also into perfectly round Globules .
(HOOKE-E3-H,47.48)

The way , in short , as I received it from the <font> Learned Physitian
Doctor </font> I. G. is this ; (HOOKE-E3-H,47.49)

Reduce the Metal you would thus shape , into exceeding fine filings ,
(HOOKE-E3-H,47.50)

the finer the filings are , the finer will the Balls be :
(HOOKE-E3-H,47.51)

<font> Stratifie </font> these filings with the fine and well dryed
powder of quick Lime in a <font> Crucible </font> proportioned to the
quantity you intend to make : (HOOKE-E3-H,47.52)

When you have thus filled your <font> Crucible </font> , by continual
<font> stratifications </font> of the filings and powder , so that , as
neer as may be , no one of the filings may touch another , place the
<font> Crucible </font> in a <font> gradual fire </font> ,
(HOOKE-E3-H,47.53)

and by degrees let it be brought to a heat big enough to make all the
filings , that are mixt with the quick Lime , to melt , and no more ;
(HOOKE-E3-H,47.54)

for if the fire be too hot , many of these filings will joyn and run
together ; whereas if the heat be proportioned , upon washing the
Lime-dust in fair Water , all those small filings of the Metal will
subside to the bottom in a most curious powder , consisting all of
exactly round <font> Globules </font> , which if it be very fine , is
very excellent to make Hour-glasses of . (HOOKE-E3-H,47.55)

Now though quick Lime be the powder that this direction makes choice of
, yet I doubt not , but that there may be much more convenient ones
found out , one of which I have made tryal of , and found very
effectual ; (HOOKE-E3-H,47.56)

and were it not for discovering , by the mentioning of it , another
Secret , which I am not free to impart , I should have here inserted it
. (HOOKE-E3-H,47.57)

<P_112>

<heading>

OBSERV. XVIII . (HOOKE-E3-H,112.60)

OF THE SCHEMATISME OR TEXTURE OF CORK , AND OF THE CELLS AND PORES OF
SOME OTHER SUCH FROTHY BODIES . (HOOKE-E3-H,112.61)

</heading>

I took a good clear piece of Cork , (HOOKE-E3-H,112.63)

and with a Pen-knife sharpen'd as keen as a Razor , I cut a piece of it
off , (HOOKE-E3-H,112.64)

and thereby left the surface of it exceeding smooth ,
(HOOKE-E3-H,112.65)

then examining it very diligently with a <font> Microscope </font> , me
thought I could perceive it to appear a little porous ;
(HOOKE-E3-H,112.66)

but I could not so plainly distinguish them , as to be sure that they
were pores , much less what Figure they were of : (HOOKE-E3-H,112.67)

But judging from the lightness and yielding quality of the Cork , that
certainly the texture could not be so <P_113> curious , but that
possibly , if I could use some further diligence , I might find it to
be discernable with a <font> Microscope </font> , I with the same sharp
Pen-knife , cut off from the former smooth surface an exceeding thin
piece of it , (HOOKE-E3-H,113.68)

and placing it on a black object Plate , because it was it self a white
body , and casting the light on it with a deep <font> plano-convex
Glass </font> , I could exceeding plainly perceive it to be all
perforated and porous , much like a Honey-comb , but that the pores of
it were not regular ; (HOOKE-E3-H,113.69)

yet it was not unlike a Honey-comb in these particulars .
(HOOKE-E3-H,113.70)

First , in that it had a very little solid substance , in comparison of
the empty cavity that was contain'd between , as does more manifestly
appear by the Figure A and B of the XI. <font> Scheme </font> ,
(HOOKE-E3-H,113.71)

for the Interstitia , or walls <paren> as I may so call them </paren>
or partitions of those pores were neer as thin in proportion to their
pores , as those thin films of Wax in a Honey-comb <paren> which
enclose and constitute the <font> sexangular cells </font> </paren> are
to theirs . (HOOKE-E3-H,113.72)

Next , in that these pores , or cells , were not very deep , but
consisted of a great many little Boxes , separated out of one continued
long pore , by certain <font> Diaphragms </font> , as is visible by the
Figure B , which represents a sight of those pores split the long-ways
. (HOOKE-E3-H,113.73)

I no sooner discern'd these <paren> which were indeed the first <font>
microscopical </font> pores I ever saw , and perhaps , that were ever
seen , for I had not met with any Writer or Person , that had made any
mention of them before this </paren> but me thought I had with the
discovery of them , presently hinted to me the true and intelligible
reason of all the <font> Phaenomena </font> of Cork ;
(HOOKE-E3-H,113.74)

As , First , if I enquir'd why it was so exceeding light a body ? my
<font> Microscope </font> could presently inform me that here was the
same reason evident that there is found for the lightness of froth , an
empty Honey-comb , Wool , a Spunge , a Pumice-stone , or the like ;
namely , a very small quantity of a solid body , extended into
exceeding large dimensions . (HOOKE-E3-H,113.75)

Next , it seem'd nothing more difficult to give an intelligible reason
, why Cork is a body so very unapt to suck and drink in Water , and
consequently preserves it self , floating on the top of Water , though
left on it never so long : and why it is able to stop and hold air in a
Bottle , though it be there very much condens'd and consequently
presses very strongly to get a passage out , without suffering the
least bubble to pass through its substance . (HOOKE-E3-H,113.76)

For , as to the first , since our <font> Microscope </font> informs us
that the substance of Cork is altogether fill'd with Air , and that
that Air is perfectly enclosed in little Boxes or Cells distinct from
one another . It seems very plain , why neither the Water , nor any
other Air can easily insinuate it self into them , since there is
already within them an <language> intus existens </language> , and
consequently , why the pieces of Cork become so good floats for Nets ,
and stopples for Viols , or other close Vessels . (HOOKE-E3-H,113.77)

And thirdly , if we enquire why Cork has such a springiness and
swelling nature $when {TEXT:whem} compress'd ? and how it comes to
suffer so great a compression , or seeming penetration of dimensions ,
so as to be made a substance as heavie again and more , bulk for bulk ,
as it was before compression , and yet suffer'd to return , is found to
extend it self again into the same space ? Our <font> Microscope
</font> will easily inform us , that the whole mass <P_114> consists of
an infinite company of small Boxes or Bladders of Air , which is a
substance of a springy nature , and that will suffer a considerable
condensation <paren> as I have several times found by divers trials ,
by which I have most evidently condens'd it into less then a twentieth
part of its usual dimensions neer the Earth , and that with no other
strength then that of my hands without any kind of forcing Engine ,
such as Racks , Leavers , Wheels , Pullies , or the like , but this
onely by and by </paren> (HOOKE-E3-H,114.78)

and besides , it seems very probable that those very films or sides of
the pores , have in them a springing quality , as almost all other kind
of Vegetable substances have , so as to help to restore themselves to
their former position . (HOOKE-E3-H,114.79)

And could we so easily and certainly discover the <font> Schematisme
</font> and <font> Texture </font> even of these films , and of several
other bodies , as we can these of Cork ; there seems no probable reason
to the contrary , but that we might as readily render the true reason
of all their <font> Phaenomena </font> , as namely , what were the
cause of the springiness , and toughness of some , both-3 as to their
flexibility and restitution . What , of the friability or brittleness
of some others , and the like ; (HOOKE-E3-H,114.80)

but till such time as our <font> Microscope </font> , or some other
means , enable us to discover the true <font> Schematism </font> and
<font> Texture </font> of all kinds of bodies , we must grope , as it
were , in the dark , and onely ghess at the true reasons of things by
similitudes and comparisons . (HOOKE-E3-H,114.81)

But , to return to our Observation . I told several lines of these
pores , (HOOKE-E3-H,114.82)

and found that there were usually about threescore of these small Cells
placed end-ways in the eighteenth part of an Inch in length , whence I
concluded there must be neer eleven hundred of them , or somewhat more
then a thousand in the length of an Inch , and therefore in a square
Inch above a Million , or . and in a Cubick Inch , above twelve hundred
Millions , or . a thing almost incredible , did not our <font>
Microscope </font> assure us of it by ocular demonstration ; nay , did
it not discover to us the pores of a body , which were they <font>
diaphragm'd </font> , like those of Cork , would afford us in one
Cubick Inch , more then ten times as many little Cells , as is evident
in several charr'd Vegetables ; (HOOKE-E3-H,114.83)

so prodigiously curious are the works of Nature , that even these
conspicuous pores of bodies , which seem to be the channels or pipes
through which the Succus {TEXT:suceus} nutritius , or natural juices of
Vegetables are convey'd , and seem to correspond to the veins ,
arteries and other Vessels in sensible creatures , that these pores I
say , which seem to be the Vessels of nutrition to the vastest body in
the World , are yet so exceeding small , that the <font> Atoms </font>
which <font> Epicurus </font> fancy'd would go neer to prove too bigg
to enter them , much more to constitute a fluid body in them .
(HOOKE-E3-H,114.84)

And how infinitely smaller then must be the Vessels of a Mite , or the
pores of one of those little Vegetables I have discovered to grow on
the back-side of a Rose-leaf , and shall anon more fully describe ,
whose bulk is many millions of times less then the bulk of the small
shrub it grows on ; and even that shrub , many millions of times less
in bulk then several trees <paren> that have heretofore grown in <font>
England </font> , and are this day flourishing in other hotter Climates
, as we are very credibly inform'd </paren> if at least the pores of
this small Vegetable should keep any such proportion to the body of it
, as we have found these pores <P_115> of other Vegetables to do to
their bulk . (HOOKE-E3-H,115.85)

But of these pores I have said more elsewhere . (HOOKE-E3-H,115.86)

To proceed then , Cork seems to be by the transverse constitution of
the pores , a kind of Fungus or Mushrome , (HOOKE-E3-H,115.87)

for the pores lie like so many Rays tending from the center , or pith
of the tree , outwards ; so that if you cut off a piece from a board of
Cork transversly , to the flat of it , you will , as it were , split
the pores , and they will appear just as they are express'd in the
Figure B of the XI. <font> Scheme </font> . (HOOKE-E3-H,115.88)

But if you shave off a very thin piece from this board , parallel to
the plain of it , you will cut all the pores transversly ,
(HOOKE-E3-H,115.89)

and they will appear almost as they are express'd in the Figure A ,
save onely the solid Interstitia will not appear so thick as they are
there represented . So that Cork seems to suck its nourishment from the
subjacent bark of the Tree immediately , and to be a kind of
excrescence , or a substance distinct from the substances of the entire
Tree , something <font> analogus </font> to the Mushrome , or Moss on
other Trees , or to the hairs on Animals . (HOOKE-E3-H,115.90)

And having enquir'd into the History of Cork , I find it reckoned as an
excrescency of the bark of a certain Tree , which is distinct from the
two barks that lie within it , which are common also to other trees ;
That $'t $is {TEXT:'tis} some time before the Cork that covers the
young and tender sprouts comes to be discernable ; That it cracks ,
flaws , and cleaves into many great chaps , the bark underneath
remaining entire ; That it may be separated and remov'd from the Tree ,
and yet the two under-barks <paren> such as are also common to that
with other Trees </paren> not at all injur'd , but rather helped and
freed from an external injury . (HOOKE-E3-H,115.91)

Thus <font> Ionstonus </font> in <font> Dendrologia </font> , speaking
de Subere , says , Arbor est procera , Lignum est robustum , dempto
cortice in aquis non fluitat , Cortice in orbem detracto juvatur ,
crascescens enim praestringit & strangulat , intra triennium iterum
repletur : Caudex ubi adolescit crassus , cortex superior densus
carnosus , duos digitos crassus , scaber , rimosus , & qui nisi
detrahatur dehiscit , alioque subnascente expellitur , interior qui
subest novellus ita rubet ut arbor minio picta videatur .
(HOOKE-E3-H,115.92)

Which Histories , if well consider'd , and the tree , substance , and
manner of growing , if well examin'd , would , I am very apt to believe
, much confirm this my conjecture about the origination of Cork .
(HOOKE-E3-H,115.93)

Nor is this kind of Texture peculiar to Cork onely ;
(HOOKE-E3-H,115.94)

for upon examination with my <font> Microscope </font> , I have found
that the pith of an Elder , or almost any other Tree , the inner pulp
or pith of the Cany hollow stalks of several other Vegetables : as of
Fennel , Carrets , Daucus , Bur-docks , Teafels , Fearn , some kinds of
Reeds , &c. have much such a kind of <font> Schematisme </font> , as I
have lately shewn that of Cork , save onely that here the pores are
rang'd the long-ways , or the same ways with the length of the Cane ,
whereas in Cork they are transverse . (HOOKE-E3-H,115.95)

The pith also that fills that part of the stalk of a Feather that is
above the Quil , has much such a kind of texture , save onely that
which way soever I set this light substance , the pores seem'd to be
cut transversly ; so that I ghess this pith which fills the Feather ,
not to consist of abundance of long pores separated with Diaphragms ,
as Cork does , but to be a kind <P_116> of solid or hardned froth , or
a <font> congeries </font> of very small bubbles consolidated in that
form , into a pretty stiff as well as tough concrete , and that each
Cavern , Bubble , or Cell , is distinctly separate from any of the rest
, without any kind of hole in the encompassing films , so that I could
no more blow through a piece of this kinde of substance , then I could
through a piece of Cork , or the sound pith of an Elder .
(HOOKE-E3-H,116.96)

But though I could not with my <font> Microscope </font> , nor with my
breath , nor any other way I have yet try'd , discover a passage out of
one of those cavities into another , yet I $can $not {TEXT:cannot}
thence conclude , that therefore there are none such , by which the
Succus nutritius , or appropriate juices of Vegetables , may pass
through them ; (HOOKE-E3-H,116.97)

for , in several of those Vegetables , whil'st green , I have with my
<font> Microscope </font> , plainly enough discover'd these Cells or
Poles fill'd with juices , and by degrees sweating them out : as I have
also observed in green Wood all those long <font> Microscopical </font>
pores which appear in Charcoal perfectly empty of any thing but Air .
(HOOKE-E3-H,116.98)

Now , though I have with great diligence endeavoured to find whether
there be any such thing in those <font> Microscopical </font> pores of
Wood or Piths , as the <font> Valves </font> in the heart , veins , and
other passages of Animals , that open , and give passage to the
contain'd fluid juices one way , and shut themselves , and impede the
passage of such liquors back again , yet have I not hitherto been able
to say any thing positive in it ; though , me thinks , it seems very
probable , that Nature has in these passages , as well as in those of
Animal bodies , very many appropriated Instruments and contrivances ,
whereby to bring her designs and end to pass , which $'t $is
{TEXT:'tis} not improbable , but that some diligent Observer , if
help'd with better <font> Microscopes </font> , may in time detect .
(HOOKE-E3-H,116.99)

And that this may be so , seems with great probability to be argued
from the strange <font> Phaenomena </font> of sensitive Plants ,
wherein Nature seems to perform several Animal actions with the same
<font> Schematism </font> or <font> Orginization </font> that is common
to all Vegetables , as may appear by some no less instructive then
curious Observations that were made by divers Eminent Members of the
<font> Royal Society </font> on some of these kind of Plants , whereof
an account was delivered in to them by the most Ingenious and Excellent
<font> Physician </font> , Doctor <font> Clark </font> , which , having
that liberty granted me by that most Illustrious Society , I have
hereunto adjoyn'd . (HOOKE-E3-H,116.100)

<P_210>

<heading>

OBSERV. LIII . (HOOKE-E3-H,210.103)

OF A FLEA . (HOOKE-E3-H,210.104)

</heading>

The strength and beauty of this small creature , had it no other
relation at all to man , would deserve a description .
(HOOKE-E3-H,210.106)

For its strength , the <font> Microscope </font> is able to make no
greater discoveries of it then the naked eye , (HOOKE-E3-H,210.107)

but onely the curious contrivance of its leggs and joints , for the
exerting that strength , is very plainly manifested , such as no other
creature , I have yet observ'd , has any thing like it ;
(HOOKE-E3-H,210.108)

for the joints of it are so adapted , that he can , as $'t $were
{TEXT:'twere} , fold them short one within another , and suddenly
stretch , or spring them out to their whole length , that is , of the
fore-leggs , (HOOKE-E3-H,210.109)

the part A , of the 34. <font> Scheme </font> , lies within B , and B
within C , parallel to , or side by side each other ;
(HOOKE-E3-H,210.110)

but the parts of the two next , lie quite contrary , that is , D
without E , and E without F , but parallel also ; (HOOKE-E3-H,210.111)

but the parts of the hinder leggs , G , H and I , bend one within
another , like the parts of a double jointed Ruler , or like the foot ,
legg and thigh of a man ; (HOOKE-E3-H,210.112)

These six leggs he clitches up altogether , (HOOKE-E3-H,210.113)

and when he leaps , springs them all out , (HOOKE-E3-H,210.114)

and thereby exerts his whole strength at once . (HOOKE-E3-H,210.115)

But , as for the beauty of it , the <font> Microscope </font> manifests
it to be all over adorn'd with a curiously polish'd suit of <font>
sable </font> Armour , neatly jointed , and beset with multitudes of
sharp pinns , shap'd almost like Porcupine's Quills , or bright conical
Steel-bodkins ; (HOOKE-E3-H,210.116)

the head is on either side beautify'd with a quick and round black eye
K , behind each of which also appears a small cavity , L , in which he
seems to move to and fro a certain thin film beset with many small
transparent hairs , which probably may be his ears ;
(HOOKE-E3-H,210.117)

in the forepart of his head , between the two fore-leggs , he has two
small long jointed feelers , or rather smellers , M M , which have four
joints , and are hairy , like those of several other creatures ;
(HOOKE-E3-H,210.118)

between these , it has a small proboscis , or <font> probe </font> , N
N O , that seems to consist of a <P_211> tube N N , and a tongue or
sucker O , which I have perceiv'd him to slip in and out .
(HOOKE-E3-H,211.119)

Besides these , it has also two chaps or biters P_N P_N , which are
somewhat like those of an Ant , (HOOKE-E3-H,211.120)

but I could not perceive them tooth'd ; (HOOKE-E3-H,211.121)

these were shap'd very like the blades of a pair of round top'd Scizers
, (HOOKE-E3-H,211.122)

and were opened and shut just after the same manner ;
(HOOKE-E3-H,211.123)

with these Instruments does this little busie Creature bite and pierce
the skin , and suck out the blood of an Animal , leaving the skin
inflamed with a small round red spot . (HOOKE-E3-H,211.124)

These parts are very difficult to be discovered , because , for the
most part , they lye covered between the fore-legs .
(HOOKE-E3-H,211.125)

There are many other particulars , which , being more obvious , and
affording no great matter of information , I shall pass by , and refer
the Reader to the Figure . (HOOKE-E3-H,211.126)

<heading>

OBSERV. LIV . (HOOKE-E3-H,211.128)

OF A LOUSE . (HOOKE-E3-H,211.129)

</heading>

This is a Creature so officious , that $'t $will {TEXT:'twill} be known
to every one at one time or other , so busie , and so impudent , that
it will be intruding it self in every ones company , and so proud and
aspiring withall , that it fears not to trample on the best , and
affects nothing so much as a Crown ; (HOOKE-E3-H,211.131)

feeds and lives very high , (HOOKE-E3-H,211.132)

and that makes it so saucy , as to pull any one by the ears that comes
in its way , (HOOKE-E3-H,211.133)

and will never be quiet till it has drawn blood : (HOOKE-E3-H,211.134)

it is troubled at nothing so much as at a man that scratches his head ,
as knowing that man is plotting and contriving some mischief against it
, (HOOKE-E3-H,211.135)

and that makes it oftentime sculk into some meaner and lower place ,
and run behind a mans back , though it go very much against the hair ;
which ill conditions of it having made it better known then trusted ,
would exempt me from making any further description of it , did not my
faithful <font> Mercury </font> , my <font> Microscope </font> , bring
me other information of it . (HOOKE-E3-H,211.136)

For this has discovered to me , by means of a very bright light cast on
it , that it is a Creature of a very odd shape ; (HOOKE-E3-H,211.137)

it has a head shap'd like that exprest in 35. <font> Scheme </font>
marked with A , which seems almost Conical , but is a little flatted on
the upper and under sides , at the biggest part of which , on either
side behind the head <paren> as it were , being the place where other
Creatures ears stand </paren> are placed its two black shining goggle
eyes B B , looking backwards , and fenced round with several small
<font> cilia </font> or hairs that incompass it , so that it seems this
Creature has no very good foresight : (HOOKE-E3-H,211.138)

It does not seem to have any eye-lids , (HOOKE-E3-H,211.139)

and therefore perhaps its eyes were so placed , that it might the
better cleanse them with its fore-legs ; (HOOKE-E3-H,211.140)

and perhaps this may be the reason , why they so much avoid and run
from the light behind them , (HOOKE-E3-H,211.141)

for being made to live in the shady and dark recesses of the hair , and
thence probably their eye having a great aperture , the open and clear
light , especially that of the Sun , must needs very much offend them ;
(HOOKE-E3-H,211.142)

to secure these eyes from receiving any injury from the hairs through
which it passes , it has <P_212> two horns that grow before it , in the
place where one would have thought the eyes should be ;
(HOOKE-E3-H,212.143)

each of these C C hath four joynts , which are fringed , as $'t $were
{TEXT:'twere} , with small brisles , from which to the tip of its snout
D , the head seems very round and tapering , ending in a very sharp
nose D , which seems to have a small hole , and to be the passage
through which he sucks the blood . (HOOKE-E3-H,212.144)

Now whereas if it be plac'd on its back , with its belly upwards , as
it is in the 35. <font> Scheme </font> , it seems in several Positions
to have a resemblance of chaps , or jaws , as is represented in the
Figure by E E , yet in other postures those dark strokes disappear ;
(HOOKE-E3-H,212.145)

and having kept several of them in a box for two or three dayes , so
that for all that time they had nothing to feed on , I found , upon
letting one creep on my hand , that it immediately fell to sucking ,
and did neither-2 seem to thrust its nose very deep into the skin , nor
to open any kind of mouth , (HOOKE-E3-H,212.146)

but I could plainly perceive a small current of blood , which came
directly from its snout , and past into its belly ;
(HOOKE-E3-H,212.147)

and about A there seem'd a contrivance , somewhat resembling a Pump ,
pair of Bellows , or Heart , (HOOKE-E3-H,212.148)

for by a very swift <font> systole </font> and <font> diastole </font>
the blood seem'd drawn from the nose , and forced into the body .
(HOOKE-E3-H,212.149)

It did not seem at all , though I viewed it a good while as it was
sucking , to thrust more of its nose into the skin then the very snout
D , (HOOKE-E3-H,212.150)

nor did it cause the least discernable pain , (HOOKE-E3-H,212.151)

and yet the blood seem'd to run through its head very quick and freely
, so that it seems there is no part of the skin but the blood is
dispers'd into , nay , even into the cuticula ; (HOOKE-E3-H,212.152)

for had it thrust its whole nose in from D to C C , it would not have
amounted to the supposed thickness of that <font> tegument </font> ,
the length of the nose being not more then a three hundredth part of an
inch . (HOOKE-E3-H,212.153)

It has six legs , covered with a very transparent shell , and joynted
exactly like a Crab's , or Lobster's ; (HOOKE-E3-H,212.154)

each leg is divided into six parts by these joynts ,
(HOOKE-E3-H,212.155)

and those have here and there several small hairs ;
(HOOKE-E3-H,212.156)

and at the end of each leg it has two claws , very properly adapted for
its peculiar use , being thereby inabled to walk very securely both-1
on the skin and hair ; (HOOKE-E3-H,212.157)

and indeed this contrivance of the feet is very curious ,
(HOOKE-E3-H,212.158)

and could not be made more commodiously and compendiously , for
performing both these requisite motions , of walking and climbing up
the hair of a mans head , then it is : (HOOKE-E3-H,212.159)

for , by having the lesser claw <paren> a </paren> set so much short of
the bigger <paren> b </paren> when it walks on the skin the shorter
touches not , (HOOKE-E3-H,212.160)

and then the feet are the same with those of a Mite , and several other
small Insects , (HOOKE-E3-H,212.161)

but by means of the small joynts of the longer claw it can bend it
round , and so with both claws take hold of a hair , in the manner
represented in the Figure , the long transparent Cylinder F F F , being
a Man's hair held by it . (HOOKE-E3-H,212.162)

The Thorax seem'd cas'd with another kind of substance then the belly ,
namely , with a thin transparent horny substance , which upon the
fasting of the Creature did not grow flaccid ; (HOOKE-E3-H,212.163)

through this I could plainly see the blood , suck'd from my hand , to
be variously distributed , and mov'd to and fro ; (HOOKE-E3-H,212.164)

and about G there seem'd a pretty big white substance , which seem'd to
be moved within its thorax ; (HOOKE-E3-H,212.165)

besides , there appear'd very many small milk-white vessels , which
crost over the breast <P_213> between the legs , out of which , on
either side , were many small branchings , (HOOKE-E3-H,213.166)

these seemd to be the veins and arteries , (HOOKE-E3-H,213.167)

for that which is analogus to blood in all Insects is milk-white .
(HOOKE-E3-H,213.168)

The belly is covered with a transparent substance likewise , but more
resembling a skin then a shell , (HOOKE-E3-H,213.169)

for $'t $is {TEXT:'tis} grain'd all over the belly just like the skin
in the palms of a man's hand , (HOOKE-E3-H,213.170)

and when the belly is empty , grows very flaccid and wrinkled ;
(HOOKE-E3-H,213.171)

at the upper end of this is placed the stomach H H ,
(HOOKE-E3-H,213.172)

and perhaps also the white spot I I may be the liver or <font> pancreas
</font> , which by the <font> peristaltick </font> motion of the guts ,
is a little mov'd to and fro , not with a <font> systole </font> and
<font> diastole </font> , but rather with a thronging or justling
motion . (HOOKE-E3-H,213.173)

Viewing one of these Creatures , after it had fasted two dayes , all
the hinder part was lank and flaccid , (HOOKE-E3-H,213.174)

and the white spot I I hardly mov'd , (HOOKE-E3-H,213.175)

most of the white branchings disappear'd , and most also of the redness
or sucked blood in the guts , the <font> peristaltick </font> motion of
which was scarce discernable ; (HOOKE-E3-H,213.176)

but upon the suffering it to suck ; it presently fill'd the skin of the
belly , and of the six scolop'd embosments on either side , as full as
it could be stuft ; (HOOKE-E3-H,213.177)

the stomach and guts were as full as they could hold ;
(HOOKE-E3-H,213.178)

the <font> peristaltick </font> motion of the gut grew quick , and the
justling motion of I I accordingly ; (HOOKE-E3-H,213.179)

multitudes of milk-white vessels seem'd quickly filled , and turgid ,
which were perhaps the veins and arteries , (HOOKE-E3-H,213.180)

and the Creature was so greedy , that though it could not contain more
, yet it continued sucking as fast as ever , and as fast emptying it
self behind : (HOOKE-E3-H,213.181)

the digestion of this Creature must needs be very quick ,
(HOOKE-E3-H,213.182)

for though I perceiv'd the blood thicker and blacker when sucked
{TEXT:suckd} , yet , when in the guts , it was of a very lovely ruby
colour , (HOOKE-E3-H,213.183)

and that part of it , which was digested into the veins , seemed white
; whence it appears , that a further digestion of blood may make it
milk , at least of a resembling colour : (HOOKE-E3-H,213.184)

What is else observable in the figure of this Creature , may be seen by
the 35. <font> Scheme </font> . (HOOKE-E3-H,213.185)