1 . (BOYLE-E3-H,8E.2) The first and most general Observation is , That Electrical Bodies draw not unless they be warm'd ; which Rule though I have now and then found to admit of an Exception , whereof I elsewhere offer an account , yet , as to the generality of common Electricks , it holds well enough to give much countenance to our Doctrine , which teaches the effects of Electrical Bodies to be perform'd by Corporeal Emanations . (BOYLE-E3-H,8E.3) For $'t $is {TEXT:'tis} known , that Heat , by agitating the parts of a fit Body , solicites it as it were to send forth its Effluvia , as is obvious in odoriferous Gums and Perfumes , which , being heated , send forth their fragrant steams , both further and more copiously than otherwise they would . (BOYLE-E3-H,8E.4) 2 . (BOYLE-E3-H,8E.5) Next , it has been observ'd , that Amber , &c. warm'd by the fire , does not attract so vigorously , as if it acquire an equal degree of heat by being chaf'd or rub'd : So that the modification of motion in the internal parts , and in the Emanations of the Amber , may , as well as the degree of it , contribute to the Attraction . (BOYLE-E3-H,9E.6) And my particular Observations incline me to adde , that the effect may oftentimes be much promoted , by employing both these ways successively ; as I thought I manifestly found when I first warm'd the Amber at the fire , and presently after chaf'd it a little upon a piece of cloth . (BOYLE-E3-H,9E.7) For then a very few rubbings seem'd to excite it more than many more would otherwise have done : As if the heat of the fire had put the parts into a general , but confus'd , agitation ; to which $'t $was {TEXT:'twas} easie for the subsequent Attrition or Reciprocation of Pressure to give a convenient modification in a Body whose Texture disposes it to become vigorously Electrical . (BOYLE-E3-H,9E.8) 3 . (BOYLE-E3-H,9E.9) Another Observation that is made about these Bodies , is , That they require Tersion as well as Attrition ; (BOYLE-E3-H,9E.10) and though I doubt whether the Rule be infallible , yet I deny not but that weaker Electricks require to be as well wip'd as chaf'd ; (BOYLE-E3-H,10E.11) and even good ones will have their Operation promoted by the same means . (BOYLE-E3-H,10E.12) And this is very agreeable to our Doctrine , since Tersion , besides that it is , as I have sometimes manifestly known it , a kind or degree of Attrition , frees the Surface from those adherences that might choak the pores of the Amber , or at least hinder the emanation of the steams to be so free and copious as otherwise it would be . (BOYLE-E3-H,10E.13) 4 . (BOYLE-E3-H,10E.14) $'T $is {TEXT:'Tis} likewise observ'd , That whereas the Magnetical Steams are so subtile , that they penetrate and perform their Operation through all kind of Mediums hitherto known to us ; Electrical Steams are like those of some odoriferous Bodies , easily check'd in their progress , since $'t $is {TEXT:'tis} affirm'd by Learned Writers , who say they speak upon particular Trial , that the interposition of the finest Linnen or Sarsnet is sufficient to hinder all the Operation of excited Amber upon a Straw or Feather plac'd never so little beyond it . (BOYLE-E3-H,11E.15) 5 . (BOYLE-E3-H,11E.16) It has been also observed , that the effects of Electrical Attraction are weaken'd if the air be thick and cloudy ; and especially if the Southwind blows : And that Electricks display their vertue more faintly by night than by day , and more vigorously in clear weather , and when the winds are Northerly . All which the Learned Kircherus asserts himself to have found true by experience ; insomuch that those bodies that are but faintly drawn when the weather is clear , will not , when $'t $is {TEXT:'tis} thick and cloudy , be at all moved . (BOYLE-E3-H,11E.17) 6 . (BOYLE-E3-H,11E.18) We have also observed , That divers Concretes , that are notably Electrical , do abound in an effluviable matter if I may so call it which is capable of being manifestly evaporated by heat and rubbing . (BOYLE-E3-H,11E.19) Thus we see , that most Resinous Gums , that draw light bodies , do also , being moderately solicited by heat , whether this be excited by the fire , or by Attrition or Contusion emit steams . (BOYLE-E3-H,12E.20) And in pieces of Sulphur conveniently shaped , I found upon due Attrition a Sulphureous stink . (BOYLE-E3-H,12E.21) And that piece of Amber which I most employ , being somewhat large and very well polish'd , will , being rub'd upon a piece of woollen cloth , emit steams , which the nostrils themselves may perceive ; (BOYLE-E3-H,12E.22) and they sometimes seem to me not unlike those that I took notice of , when I kept in my mouth a drop or two of the diluted Tincture or Solution of the finer parts of Amber made with Spirit of Wine , or of Sal Armoniac . (BOYLE-E3-H,12E.23) 7 . (BOYLE-E3-H,12E.24) It agrees very well with what has been said of the corporeal Emanations of Amber , that its attractive power will continue some time after it has been once excited . (BOYLE-E3-H,12E.25) For the Attrition having caus'd an intestine commotion in the parts of the Concrete , the heat or warmth that is thereby excited ought not to cease , as soon as ever the rubbing is over , but to continue capable of emitting Effluvia for some time afterwards , which will be longer or shorter according to the goodness of the Electric , and the degree of the Antecedent commotion : which joyn'd together may sometimes make the effect considerable , insomuch that in a warm day , about noon , I did with a certain body , not much , if at all , bigger than a Pea , but very vigorously attractive , move to and fro a Steel Needle freely poysed , about three minutes or the twentieth part of an hour after I had left off rubbing the Attrahent . (BOYLE-E3-H,13E.26) 8 . (BOYLE-E3-H,13E.27) That it may not seem impossible , that Electrical Effluvia should be able to insinuate themselves into the pores of many other bodies , I shall adde , that I found them subtile enough to attract not onely Spirit of Wine , but that of {HELSINKI:'of'_missing} the fluid aggregate of Corpuscles we call Smoak . (BOYLE-E3-H,13E.28) For having well lighted a Wax-taper , which I preferr'd to a common Candle to avoid the stink of the snuff , I blew out the flame ; (BOYLE-E3-H,13E.29) and , when the smoak ascended in a slender stream , held , at a convenient distance from it , an excited piece of Amber or a chafed Diamond , which would manifestly make the ascending smoak deviate from its former line , and turn aside , to beat , as it were , against the Electric , which , if it were vigorous , would act at a considerable distance , and seemed to smoak for a pretty while together . (BOYLE-E3-H,14E.30) 9 . (BOYLE-E3-H,14E.31) That $'t $is {TEXT:'tis} not in any peculiar Sympathy between an Electric and a body whereon it operates , that Electrical Attraction depends , seems the more probable , because Amber , for instance , does not attract onely one determinate sort of bodies , as the Loadstone does Iron , and those bodies wherein it abounds ; (BOYLE-E3-H,14E.32) but as far as I have yet tried , it draws indifferently all bodies whatsoever , being plac'd within a due distance from it , as my choicest piece of Amber draws not onely Sand and Mineral Powders , but Filings of Steel and Copper , and beaten Gold it self provided they be minute or light enough , except perhaps it be fire : (BOYLE-E3-H,15E.33) I employ the word perhaps , because I am not yet so clear in this point . (BOYLE-E3-H,15E.34) For having applied a strong Electric at a convenient distance to small fragments of ignited matter , they were readily enough attracted , (BOYLE-E3-H,15E.35) and shin'd , whilst they were sticking to the body that had drawn them : (BOYLE-E3-H,15E.36) But when I look'd attentively upon them , I found the shining sparks to be , as it were , cloath'd with light ashes , which , in spite of my diligence , had been already form'd about the attracted Corpuscles , upon the expiring of a good part of the fire ; so that it remain'd somewhat doubtful to me , whether the ignited Corpuscles , whilst they were totally such , were attracted ; or whether the immediate objects of the Attraction were not the new form'd ashes , which carried up with them those yet unextinguished parts of fire , that chanc'd to be lodg'd in them . (BOYLE-E3-H,15E.37) But , as for flame , our Countreyman Gilbert delivers as his Experiment , That an Electric though duly excited and applied , will not move the flame of the slenderest Candle . Which some will think not so easie to be well tried with common Electricks , as Amber , hard Wax , Sulphur , and the like unctuous Concretes , that very easily take fire : (BOYLE-E3-H,16E.38) Therefore I chose to make my Trial , with a rough Diamond extraordinarily attractive , which I could , without injuring it , hold as near as I pleas'd to the flame of a Candle or Taper ; (BOYLE-E3-H,16E.39) and though I was not satisfi'd that it did either attract the flame , as it visibly did the smoak , or manifestly agitate it ; yet granting that Gilbert's Assertion will constantly hold true , and so , that flame is to be excepted from the general Rule , yet this exception may well comport with the Hypothesis hitherto countenanc'd , since it may be said , as $'t $is {TEXT:'tis} , if I mistake not , by Kirkerus , that the heat of the flame dissipates the Effluvia , by whose means the Attraction should be perform'd . To which I shall adde , that possibly the Celerity of the motion of the Flame upwards , may render it very difficult for the Electrical Emanations to divert the Flame from its Course . (BOYLE-E3-H,17E.40) . (BOYLE-E3-H,17E.41) We have found by Experiment , That a vigorous and well excited piece of Amber will draw , not onely the powder of Amber , but less minute fragments of it . (BOYLE-E3-H,17E.42) And as in many cases one contrary directs to another , so this Trial suggested a further , which , in case of good success , would probably argue , that in Electrical Attraction not onely Effluvia are emitted by the Electrical body , but these Effluvia fasten upon the body to be drawn , and that in such a way , that the intervening viscous strings , which may be supposed to be made up of those cohering Effluvia , are , when their agitation ceases , contracted or made to shrink inwards towards both ends , almost as a highly strech'd Lute-string does when $'t $is {TEXT:'tis} permitted to retreat into shorter Dimensions . (BOYLE-E3-H,18E.43) But the Conjecture it self was much more easie to be made than the Experiment requisite to examine it . (BOYLE-E3-H,18E.44) For we found it no easie matter to suspend an Electric , great and vigorous enough , in such a manner , that it might , whilst suspended , be excited , and be so nicely poised , that so faint a force as that wherewith it attracts light bodies should be able to procure a Local Motion to the whole Body it self . (BOYLE-E3-H,18E.45) But after some fruitless attempts with other Electricks , I had recourse to the very vigorous piece of polish'd Amber , formerly mention'd , (BOYLE-E3-H,18E.46) and when we had with the help of a little Wax suspended it by a silken thread , we chafed very well one of the blunt edges of it upon a kind of large Pin-cushion cover'd with a course and black woollen stuff , (BOYLE-E3-H,18E.47) and then brought the Electric , as soon as we could , to settle notwithstanding its hanging freely at the bottom of the string . (BOYLE-E3-H,18E.48) This course of rubbing on the edge of the Amber we pitch'd upon for more than one reason ; (BOYLE-E3-H,19E.49) for if we had chafed the flat side , the Amber could not have approached the body it had been rub'd on without making a change of place in the whole Electric , and , which is worse , without making it move contrary to the nature of heavy bodies somewhat upwards ; whereas the Amber having , by reason of its suspension , its parts counterpoised by one another ; to make the excited edge approach to another body , that edge needed not at all ascend , but onely be moved horizontally , to which way of moving the gravity of the Electric which the string kept from moving downwards could be but little or no hinderance . (BOYLE-E3-H,19E.50) And agreeably to this we found , that if , as soon as the suspended and well rubb'd Electric was brought to settle freely , we applied to the chafed edge , but without touching it , the lately mention'd Cushion , which , by reason of its rough Superficies and porosity , was fit for the Electrical Effluvia to fasten upon , the edge would manifestly be drawn aside by the Cushion steadily held , and if this were slowly removed , would follow it a good way ; (BOYLE-E3-H,20E.51) and when this body no longer detain'd it , would return to the posture wherein it had settled before . (BOYLE-E3-H,20E.52) And this power of approaching the Cushion by vertue of the operation of its own steams , was so durable in our vigorous piece of Amber , that by once chafing it , I was able to make it follow the Cushion no less than ten or eleven times . (BOYLE-E3-H,20E.53) Whether from such Experiments one may argue , that $'t $is {TEXT:'tis} but , as $'t $were {TEXT:'twere} , by accident that Amber attracts another body , and not this the Amber ; and whether these ought to make us question , if Electricks may with so much propriety , as has been hitherto generally supposed , be said to Attract , are doubts that my Design does not here oblige me to examine . (BOYLE-E3-H,20E.54) Some other Phaenomena might be added of the same Tendency with those already mention'd , as the advantage that Electrical Bodies usually get by having well polish'd or at least smooth Surfaces , (BOYLE-E3-H,21E.55) but the Title of this Paper promising some Experiments about the Production of Electricity , I must not omit to recite , how I have been sometimes able to produce or destroy this Quality in certain bodies , by means of alterations , that appear'd not to be other than Mechanical . (BOYLE-E3-H,21E.56) EXPER. I . (BOYLE-E3-H,21E.58) And first , having with a very mild heat slowly evaporated about a fourth part of good Turpentine , I found , that the remaining body would not , when cold , continue a Liquor , but harden'd into a transparent Gum almost like Amber , which , as I look'd for , proved Electrical . (BOYLE-E3-H,21E.60) EXPER. II . (BOYLE-E3-H,22E.63) Secondly , by mixing two such liquid Bodies as Petroleum and strong Spirit of Nitre in a certain proportion , and then distilling them till there remained a dry mass , I obtain'd a brittle substance as black as Jet ; and whose Superficies where it was contiguous to the Retort was glossie like that Mineral when polished ; (BOYLE-E3-H,22E.65) and as I expected I found it also to resemble Jet , in being endowed with an Electrical Faculty . (BOYLE-E3-H,22E.66) EXPER. III . (BOYLE-E3-H,22E.68) Thirdly , Having burnt Antimony to ashes , and of those ashes , without any addition , made a transparent Glass , I found , that , when rubb'd , as Electrical Bodies ought to be to excite them , it answer'd my expectation , by manifesting a not inconsiderable Electricity . (BOYLE-E3-H,22E.70) And this is the worthier of notice , because , that as a Vitrum Antimonii , that is said to be purer than ordinary , may be made of the Regulus of the same Mineral , in whose preparation you know a great part of the Antimonial Sulphur is separated and left among the Scoriae ; so Glass of Antimony made without additament , may easily , as experience has inform'd us , be in part reduced to a Regulus , a Body not reckon'd amongst Electrical ones . (BOYLE-E3-H,23E.71) And that you may not think , that $'t $is {TEXT:'tis} onely some peculiar and fixt part of the Antimony that is capable of Vitrification , let me assure you , that even with the other part that is wont to flye away , namely the Flowers an Antimonial Glass may without an addition of other Ingredients be made . (BOYLE-E3-H,23E.72) EXPER. IV . (BOYLE-E3-H,23E.74) Fourthly , The mention of a Vitrified Body brings into my mind , that I more than once made some Glass of Lead per se , which I found not very easie work that also was not wholly destitute of an Electrical Vertue , though it had but a very languid one . (BOYLE-E3-H,24E.76) And it is not here to be overlook'd , that this Glass might easily be brought to afford again malleable Lead , which was never reckon'd , that I know of , among Electrical Bodies . (BOYLE-E3-H,24E.77) EXPER. V . (BOYLE-E3-H,24E.79) Fifthly , Having taken some Amber , and warily distill'd it , not with Sand , or powder'd Brick , or some such additament as Chymists are wont to use , for fear it should boyl over or break their Vessels ; but by it self , that I might have an unmixed Caput mortuum ; Having made this Distillation , I say , and continued it till it had afforded a good proportion of phlegm , Spirit , Volatile Salt , and Oyl , the Retort was warily broken , (BOYLE-E3-H,24E.81) and the remaining matter was taken out in a lump , which , though it had quite lost its colour being burnt quite black , and though it were grown strangely brittle in comparison of Amber , so that they who believe the vertue of attracting light Bodies to flow from the substantial form of Amber , would not expect it in a Body so changed and deprived of its noblest parts : Yet this Caput mortuum was so far from having lost its Electrical Faculty , that it seemed to attract more vigorously than Amber it self is wont to do before it be committed to Distillation . (BOYLE-E3-H,25E.82) And from the foregoing Instances afforded us by the Glass of Antimony , we may learn , that when the form of a Body seems to be destroyed by a fiery Analysis that dissipates the parts of it , the remaining substance may yet be endowed with Electricity , as the Caput mortuum of Amber may acquire it ; as in the case of the Glass of Antimony made of the Calx and of the Flowers . (BOYLE-E3-H,25E.83) And from the second Example abovementioned , and from common Glass which is Electrical , we may also learn , that Bodies that are neither of them apart observed to be endowed with Electricity , may have that Vertue result in the compounded substance that they constitute , though it be but a factitious Body . (BOYLE-E3-H,26E.84) To the foregoing Experiments , whose success is wont to be uniform enough , I shall adde the Recital of a surprising Phaenomenon , which , though not constant , may help to make it probable , that Electrical Attractions need not be suppos'd still to proceed from the substantial , or even from the essential Form of the Attrahent ; but may be the effects of unheeded , and , as it were , fortuitous Causes . (BOYLE-E3-H,26E.85) And however , I dare not suppress so strange an Observation , (BOYLE-E3-H,26E.86) and therefore shall relate that which I had the luck to make of an odd sort of Electrical Attraction as it seem'd , not taken notice of that I know of by any either Naturalist or other Writer , (BOYLE-E3-H,26E.87) and it is this . (BOYLE-E3-H,26E.88) EXPER. VI . (BOYLE-E3-H,27E.91) That false Locks as they call them of some Hair , being by curling or otherwise brought to a certain degree of driness , or of stiffness , will be attracted by the flesh of some persons , or seem to apply themselves to it , as Hair is wont to do to Amber or Jet excited by rubbing . Of this I had a Proof in such Locks worn by two very Fair Ladies that you know . (BOYLE-E3-H,27E.93) For at some times I observed , that they could not keep their Locks from flying to their Cheeks , and though neither of them made any use , or had any need of Painting from sticking there . (BOYLE-E3-H,27E.94) When one of these Beauties first shew'd me this Experiment , I turn'd it into a Complemental Raillery , as suspecting there might be some trick in it , though I after saw the same thing happen to the others Locks too . (BOYLE-E3-H,27E.95) But as she is no ordinary Virtuosa , she very ingeniously remov'd my suspicions , (BOYLE-E3-H,28E.96) and as I requested gave me leave to satisfie my self further , by desiring her to hold her warm hand at a convenient distance from one of those Locks taken off and held in the air . (BOYLE-E3-H,28E.97) For as soon as she did this , the lower end of the Lock , which was free , applied it self presently to her hand : which seem'd the more strange , because so great a multitude of Hair would not have been easily attracted by an ordinary Electrical Body , that had not been considerably large , or extraordinarily vigorous . (BOYLE-E3-H,28E.98) This repeated Observation put me upon inquiring among some other young Ladies , whether they had observed any such like thing , (BOYLE-E3-H,28E.99) but I found little satisfaction to my Question , except from one of them eminent for being ingenious , who told me , that sometimes she had met with these troublesome Locks ; but that all she could tell me of the Circumstances , which I would have been inform'd about , was , that they seem'd to her to flye most to her Cheeks when they had been put into a somewhat stiff Curle , and when the Weather was frosty . (BOYLE-E3-H,29E.100) Some years after the making the Experiments about the Production of Electricity , having a desire to try , whether in the Attractions made by Amber , the motions excited by the air had a considerable Interest , or whether the Effect were not due rather to the Emission and Retraction of Effluvia , which being of a viscous nature may consist of Particles either branch'd or hookt , or otherwise fit for some kind of Cohesion , and capable of being stretch'd , and of shrinking again , as Leather Thongs are : To examine this , I say , I thought the fittest way , if $'t $were {TEXT:'twere} practicable , would be , to try , whether Amber would draw a light Body in a Glass whence the air was pumpt out . (BOYLE-E3-H,29E.101) And though the Trial of this seem'd very difficult to make , and we were somewhat discouraged by our first attempt , wherein the weight of the ambient air broke our Receiver , which chanced to prove too weak , when the internal air had been with extraordinary diligence pumpt out ; yet having a vigorous piece of Amber , which I had caus'd to be purposely turn'd and polish'd for Electrical Experiments , I afterwards repeated the Trial , (BOYLE-E3-H,30E.102) and found , that in warm Weather it would retain a manifest power of attracting for several minutes for it stirred a pois'd Needle after above 1$$4 of an hour after we had done rubbing it . Upon which encouragement we suspended it , being first well chafed , in a Glass Receiver that was not great , just over a light Body ; (BOYLE-E3-H,30E.103) and making haste with our Air-Pump to exhaust the Glass , when the Air was withdrawn , we did by a Contrivance let down the suspended Amber till it came very near the Straw or Feather , (BOYLE-E3-H,30E.104) and perceived , as we expected , that in some Trials , upon the least Contact it would lift it up ; and in others , for we repeated the Experiment , the Amber would raise it without touching it , that is , would attract it . (BOYLE-E3-H,30E.105) You will probably be the less dispos'd to believe , That Electrical Attractions must proceed from the Substantial Forms of the Attrahents , or from the Predominacy of this or that Chymical Principle in them , if I acquaint you with some odd Trials wherein the Attraction of light Bodies seem'd to depend upon very small circumstances . (BOYLE-E3-H,31E.106) And though forbearing at present , to offer you my thoughts about the cause of these surprising Phaenomena , I propose it onely as a Probleme to your self and your curious Friends , (BOYLE-E3-H,31E.107) yet the main circumstances seeming to be of a Mechanical Nature , the recital of my Trials will not be impertinent to the Design and Subject of this Paper . (BOYLE-E3-H,31E.108) EXPER. VII . (BOYLE-E3-H,31E.110) I Took then a large and vigorous piece of Amber conveniently shaped for my purpose , and a downy feather , such as grows upon the Bodies , not Wings or Tails of a somewhat large Chicken : (BOYLE-E3-H,31E.112) Then having moderately excited the Electrick , I held the Amber so near it , that the neighbouring part of the feather was drawn by it and stuck fast to it ; (BOYLE-E3-H,31E.113) but the remoter parts continued in their former posture . (BOYLE-E3-H,31E.114) This done , I applyed my fore-finger to these erected downy feathers , (BOYLE-E3-H,32E.115) and immediately , as I expected , they left their preceeding posture , (BOYLE-E3-H,32E.116) and applied themselves to it as if it had been an Electrical Body . (BOYLE-E3-H,32E.117) And whether I offered to them my nail , or the pulpy part of my finger , or held my finger towards the right hand or the left , or directly over , these downy feathers that were near the little Quill did nimbly , and , for ought appear'd , equally turn themselves towards it , and fasten themselves to it . (BOYLE-E3-H,32E.118) And to shew that the steams that issued out of so warm a Body as my finger were not necessary to attract as men speak the abovementioned feathers , instead of my finger , I applied to them , after the same manner , a little Cylindrical Instrument of Silver , to which they bowed and fastened themselves as they had done to my finger , though the tip of this Instrument were presented to them in several postures . (BOYLE-E3-H,32E.119) The like success I had with the end of an Iron Key , and the like also with a cold piece of polish'd black Marble ; (BOYLE-E3-H,32E.120) and sometimes the feathers did so readily and strongly fasten themselves to these extraneous and unexcited Bodies , that I have been able though not easily to make one of them draw the feather from the Amber it self . (BOYLE-E3-H,33E.121) But it is diligently to be observ'd , that this unusual attraction happened onely whilst the electrical operation of the excited Amber continued strong enough to sustain the feathers . (BOYLE-E3-H,33E.122) For afterwards , neither the approach of my finger , nor that of the other bodies , would make the downy feathers change their posture . (BOYLE-E3-H,33E.123) Yet as soon as ever the Amber was by a light affriction excited again , the feather would be disposed to apply it self again to the abovementioned Bodies . (BOYLE-E3-H,33E.124) And lest there should be any peculiarity in that particular feather , I made the Trials with others provided they were not long enough to exceed the sphere of activity of the Amber (BOYLE-E3-H,33E.125) and found the Experiment to answer my expectation . (BOYLE-E3-H,33E.126) I made the Experiment also at differing times , and with some months , if not rather years , of interval , but with the like success . (BOYLE-E3-H,34E.128) And lest you should think these Phaenomena proceed from some peculiarity in the piece of Amber I employed , I shall add , that I found uniformity enough in the success , when , in the place of Amber , I substituted another Electrick , and particularly a smooth mass of melted Brimstone . (BOYLE-E3-H,34E.129) These are the Phaenomena I thought fit to mention at present of this unusual way of drawing light bodies , (BOYLE-E3-H,34E.130) and with this Experiment I should conclude my Notes about Electricity , but that I think it will not be amiss before I take leave of this Subject , to give this Advertisement , That the event of Electrical Experiments is not always so certain as that of many others , being sometimes much varied by seemingly slight circumstances , and now and then by some that are altogether over-look'd . (BOYLE-E3-H,34E.131) This Observation may receive credit from some of the particulars above recited especially concerning the interest of the weather , &c. in Electrical Phaenomena . (BOYLE-E3-H,35E.132) But now I shall add , that , not onely there may happen some variations in the success of Trials made with Electrical Bodies , but that it is not so certain as many think , whether some particular Bodies be or be not Electrical . (BOYLE-E3-H,35E.133) For the inquisitive Kircherus reckons Crystall among those Gems to whom Nature has denyed the attractive power we are speaking of ; (BOYLE-E3-H,35E.134) and yet I remember not , that , among all the trials I have made with native Crystall , I have found any that was destitute of the power he refuses them . (BOYLE-E3-H,35E.135) Also a late most learned Writer reciting the Electricks , reckon'd up by our industrious Countryman Gilbert , and increasing their number by some observed by himself , to which I shall now add , besides white Saphyrs , and white English Amethysts , the almost Diaphanous spar of Lead Ore denies Electricity to a couple of transparent Gems , the Cornelion and the Emrald . (BOYLE-E3-H,35E.136) And I do the less wonder he should do so to the former , because I have my self in vain tried to make any attraction with a piece of Cornelion so large and fair , that $'t $was {TEXT:'twas} kept for a rarity ; (BOYLE-E3-H,35E.137) and yet with divers other fine Cornelions I have been able to attract some light bodies very manifestly , if not briskly ; (BOYLE-E3-H,36E.138) and I usually wear a Cornelian Ring , that is richly enough endowed with Electricity . (BOYLE-E3-H,36E.139) But as for Emralds , as I thought it strange that Nature should have denied them a Quality she has granted to so many other Diaphanous Gems , and even to Crystal , so I thought the assertion deserved an Examen , upon which I concluded , that at least it does not universally and constantly hold true . (BOYLE-E3-H,36E.140) I had indeed seen in a Ring a Stone of price and great lustre , which , though green , I found to be , as I guess'd it would prove vigorously enough Electrical . (BOYLE-E3-H,36E.141) But this Experiment , though seemingly conclusive , I did not look upon as a fair trial , because the Stone was not a true Emrald , but , which is rare , a green Saphir . (BOYLE-E3-H,36E.142) And I learned by inquiry of the skillful Jeweller that cut it , that it was so far from having the softness of an Emrald , that he found it harder than blew Saphyrs themselves , which yet are Gems of great hardness , and by some reputed second to none , but Diamonds . (BOYLE-E3-H,36E.143) Without therefore concluding any thing from this Experiment , save that , if the assertion I was to examin were true , the want of an Electrical faculty might be thought a Concomitant rather of the peculiar Texture of the Emrald than of its green colour , I proceeded to make trial with three or four Emralds , whose being true was not doubted , (BOYLE-E3-H,37E.144) and found them all somewhat , though not equally , endow'd with Electricity , which I found to be yet more considerable in an Emrald of my own , whose colour was so excellent , that by skilful persons $'t $was {TEXT:'twas} look'd on as a rarity . (BOYLE-E3-H,37E.145) And though , by this success of my inquiry , I perceived I could not , as else I might have done , shew the Curious a new way of judging of true and false Emralds , yet the like way may be , though not always certain , yet oftentimes of use , in the estimating whether Diamonds be true or {HELSINKI:of} counterfeit , especially , if , being set in Rings , the surest way of trying them $can $not {TEXT:cannot} conveniently be employed . (BOYLE-E3-H,37E.146) For whereas Glass , though it have some Electricity , seems , as far as I have observed , to have but a faint one , there are often found Diamonds that have a very vigorous one . (BOYLE-E3-H,37E.147) And I do not remember I met with any Electrick of the same bulk , that was more vigorous than a rough Diamond I have , which is the same that I formerly mentioned to have moved a Needle above three minutes after I had ceased to chafe it . (BOYLE-E3-H,37E.148) And this brings to my mind , that it has been observed , that Diamonds draw better whilst rough , than they do after they are cut and polish'd ; which seeming to contradict what has been observed by others and by us also , that Amber , for instance , attracts more vigorously if the surface be made very smooth than otherwise , it induces me to conjecture , that , if this Observation about Diamonds be true , as some of my trials have now and then inclined me to think it , and if it do not in some cases considerably depend upon the loss of the Electrical Substance of the Stone , by its being cut and ground , the Reason may possibly be , that the great rapidness with which the Wheels that serve to cut and polish Diamonds must be mov'd , does excite a great degree of heat , which the senses may easily discover in the Stone , and by that and the strong concussion it makes of its parts , may force it to spend its effluviable matter , if I may so call it , so plentifully , that the Stone may be impoverish'd and perhaps also , on the account of some little change in its Texture , be rendred lesse disposed to emit those effluvia that are Instruments of Electrical Attraction . (BOYLE-E3-H,38E.149) But as I willingly leave the matter of Fact to further Trial , so I do the Cause of it , in case it prove true , to farther Inquiry . (BOYLE-E3-H,38E.150) Finis . (BOYLE-E3-H,38E.151)