prefents. Her emiffaries ftirred up everywhere the foldiery against the family of the Narifkins, and principally against the two Narifkins, brothers of the young Czarina dowager, mother of Peter the Firft. The Strelitz were perfuaded that John, one of thefe brothers, had taken the robes of a Czar, had placed hintelf on the throne, and had attempted to ftrangle the Prince Ivan; and to this was added the poisoning of the Czar Fodor by a Dutch phyfician, called Daniel Vangad. In short, Sophia had put into their hands a list of 40 Lords, whom the called their enemies, and thofe of the state, and whom there was a neceffity of maffacring. Examples of fuch horrors have been seen in all countries, in the times of trouble and anarchy. · The Knes Dolgorouki and Matheoff were the first that the tragic fcene opened with; they were thrown out of the windows: The Strelitz receive them on the point of their pikes, ftrip and drag them into the great fquare; foon after, entering the palace, they find there Athanafius Narifkin, brother of the young Czarina, and one of the Czar Peter's uncles; they maffacre him in the fame manner; they force open the gates of a neighbouring church, where three of the profcribed had taken refuge; they tear them from the altar, ftrip and stab them to death with knives. Their fury was fo blird, that, seeing a young Lord of the houfe of Soltikoff, pafs by, whom they loved, and who was not on the lift of the profcribed, fome of them, having taken him for John Narifkin, the perfon they were in queft of, killed him on the fpot. What fhews exactly the manners of thofe times, is, that, having difcovered their error, they carried young Soltikoff's body to his father, for interment, and the unhappy father, far from daring to complain, rewarded them for having brought to him the bloody body of his fon. His wife, daughters, and the wife of the flain, bathed in tears, upbraided him with his weakness. Let us wait for the time of vengeance:' faid the old Gentleman to them. Some Strelitz, over-hearing thefe words, furioufly break into the chamber, drag the father by his hoary locks, and cut his throat before the door of his houfe. Other Strelitz ran about, seeking everywhere after the Dutch phyfician Vangad; meeting his fon, they ask him where his father is; the young man, trembling, anfwers that he does not know, and for his answer has his throat cut. They find another phyfician, a German: You are a phyfician, fay they, if you have not poifoned our Maf ter Fodor, you have poifoned others; you deferve death:' and they kill him. At last they find the Hollander they were feeking for; he was in the disguise of a beggar; they drag him before the palace; the Princeffes, who loved and confided in him, beg earnestly for his pardon, affuring the Strelitz that he is a very good physician, and that he had very well treated their brother Fodor. The Strelitz answer, that not only he deferves death as a phyfician, but also as a forcerer, having found at his house a great dried toad, and the skin of a ferpent. They add, that the young Ivan Narifkin must be delivered up to them, whom they had in vain fought after for two days; that he was furely kept concealed in the palace; and that they would fet fire to it, if their victim was not given to them. Ivan Narifkin's sister, and the other Princeffes, terrified, ran to his retreat; the Patriarch hears his confeffion, gives him the Viaticum and Extreme Unction; after which, taking an image of the Virgin, reputed miraculous, he leads forth the young man by the hand, and advances to the Strelitz, fhewing them the Virgin's image. The Princeffes, in tears, furround Narifkin, kneel before the foldiers, conjure them, in the name of the Virgin, to grant life to their relation; but they, wrefting him out of their hands, drag him to the bottom of the ftairs with Vangad; then, forming among themselves a kind of Court of Judicature, they put interrogatories to the prifoners; and one of them, who knew how to write, draws up an indictment against them. The unfortunate Narifkin and phyfician were condemned to be cut or hacked in pieces: It is the ufual punishment in China and Tartary for parricides, and called the punishment of ten thoufand bits, or flices. After treating them in this manner, they exposed their heads, 'feet, and hands on the iron fpikes of a balustrade. Whilft they were thus glutting their rage, before the eyes of the Princeffes, others were maffacring all thofe that were odious to them, or fufpected by Sophia. This horrible execution ended by proclaiming Sovereigns, in June 1682, the two Princes, Ivan and Peter, affociating with them their fifter Sophia, in quality of coregent. She then approved of all their crimes, and rewarded them; the confifcated the eftates and poffeffions of the profcribed, and gave them to the affaffins; the even permitted them to erect a monument, on which were cut the names of those whom they had maffacred, as traitors to the country. In fine, fhe granted them letters patent, whereby fhe thanked them for their zeal and fidelity. ELEMENTS ELEMENTS of PHILOSOPHY, continued from Page 367 of our Supplement. Of the FIGURE of BODIES. of bodies? gures of bodies belong only to large compounded bodies, to thofe we can fee and touch, without any affiftance from art? Or WHAT is the figure ong diem- does it belong equally to the molecules of felves, affumed by the furfaces which terminate the volume of bodies. Q. Are there bodies that refemble each other in figure? A. It may be faid, with great probability, that all nature does not afford two bodies perfectly alike, efpecially if the diverfity of figure be joined to that of colour and volume. In a multitude of people, how great foever, two refembling faces will never be found. The operations of chemistry alfo inform us, that fome bodies, which to our fenfes appear compofed of very fimilar parts, are really compofed of very diffimilar; and this may be a reafon to prefume, that the bodies which chemistry has not been yet able to refolve are likewife compofed of diffimilar parts. Q. Do the elements great bodies are compofed of refemble one another in figure, or are they of a different figure, each according to its kind? A. Nothing pofitive can be faid in regard to this question: Thefe primordial bodies are fo finall, that they cannot be perceived, even by the help of the best microfcopes. Some philofophers pretend, that thofe which form light are all both of the fame bignefs and figure, because our eyes are conftantly after the fame manner affected by them. Q. Does not the difference obferved in the figure of compound bodies prove that there is alfo a difference in the figure of their ele ments? A. This difference in the figure of compound bodies may be the effect of the manner the elements are difpofed and ranged in. Q. How are compound bodies formed? A. They are formed by the union and affemblage of elements. If thefe elements touch one another by a great number of their furfaces, they will form a folid mafs; but, if only by fome of their furfaces, they will leave vacuums, or pores between them. Q. On what does the nature of compound bodies depend? A. It depends on the different mixtures in their formation. When thefe bodies are diffolved, the different elements they are compofed of do not lofe, on that account, their figure, because they are indivifible, and, remaining fuch as they were, might afterwards form new bodies by their mixture and union. Q. Does this prodigious variety of the fi 、 the fame bodies? Does it extend to those that efcape our fight, or are not perceptible but when there are many of them together? A. The figure of bodies being, in general, but an affemblage of furfaces that terminate a certain portion of matter, it is evident that a body, howfoever little, will be always terminated by furfaces, and confequently figured. Q. Does art difcover to us, in fmall bodies, the figures that escape our fenfes ? A. We have an abundance of curious examples of fuch difcoveries, which could never have been made without the help of microfcopes, whereof the ancients had no knowledge. Here are fome of these examples: When you caft your eye upon a grain of common fand, it appears to you as a point; the eye confounds its dimenfions; but, with the help of a microfcope, the object appears to you infinitely greater; you eafily distinguish lines in it, angles, finuofities, contours, furfaces, in a word, a figure well terminated, of which the diverfities are readily perceived, when compared with fome other. If your microfcope is good, you will perceive grains of fand, tranfparent as crystals, of the bigness of a nutmeg, angular, differently cut, and fuch as they are reprefented in the first of the annexed figures. Art applies fuccessfully grains of fand to different ufes: Becaufe they are fmall, hard, and angular, they are commodiously used for fcouring or cleaning metals, or any other ftill harder body, on which the file, or cutting of fteel, cannot properly act any longer. On account of their transparency, they become the basis of all glass-works. Leave to dry fome drops of falt water on the glafs of a microfcope, view them afterwards by the help of this inftrument, and you will perceive molecules (fig. 2.) which appear with like figures, when the preparation has been made with the fame falt. If, for instance, common falt has been used, what is perceived by the microfcope refembles little cubes. The parts of this falt, water had divided and kept diffolved, have been fixed on the glafs, whilft the liquid part evaporated. Before this evaporation of the wa ter, the affistance of the microfcope will not be fufficient to make them vifible, being then too divided and thin to be perceptible; but, according as the liquor leaves them, they affemble and form molecules of a greater volume; and, though they fhould remain as fmall as they were in the water, experience fhews, in regard to equal fize, that tranfpa. rent bodies are better feen, when plunged in air, than any other more material liquid. Every cryftallifed falt affects ufually a figure peculiar to it, and which probably depends on the figure of its leffer parts. Seafalt, for inftance, forms cubes, falt-petre needles, (fig. 3.) and fugar globules, (fig. 4.) The uniformity of figures in the molecules is not a peculiar quality of the falts; feveral other examples are met with, efpecially in the mineral kind: Rock crystal, and the greater part of transparent ftones, appear pretty often in fmall, as well as in large quantities, under the form of a prifm, or exagonal pyramid; but it fhould not thence be concluded in general, that the infenfible parts of all bodies are fo many fmall models of what they are in a larger volume. From thence proceeds, perhaps, that invariable contancy of fpecies, as well among animals as vegetables, metals, and minerals. water. Q. What is understood by compreffibility? A. It is neceflary first to know, that the relation of the volume of a body to its mafs is what is called denfity. A body is more denfe than another, when the real quantity of its matter differs lefs from its appa rent fize; or when, under a given fize, it contains more folid parts. Lead is more denfe than copper, and air lefs dense than But the fame body may change its dentity; that is, its mafs remaining the fame, its volume may vary, either by augmentation or diminution. When a body becomes more denfe, its folid parts are contracted into a lefs fpace; and that may be done two ways, either when an internal caufe is fuppreffed, that kept them more afunder, or when a force is applied exteriorly, to oblige them to come close together. The first manner of diminishing the volume of a body may be called condenfation, and the second compreffion, though, in truth, it is always condenfing a matter, whatsoever way its volume is diminished. Thus, to fqueefe fnow in the hand, in order to make a ball of it, is compreffing it; to cool a liquor, or diminish the heat that dilates its parts, is to condense it. Q. Is there no volume of a body in nature but may be diminished by compreffion or condenfation? A. Not one, except the atoms, or elementary parts of bodies. There are no compound bodies without pores, no matter perfectly hard and folid. A bar of iron, made red-hot, becomes more dense, more hard, and occupies a les volume as it cools, because its parts contract by degrees, on losing the violent motion they had acquired in the fire. A fpunge made wet, and dilated by the water it contains, occupies a much less fpace, when the fluid that filled its pores is fqueefed out. The rebounding of a marble or glass bowl, and even of a diamond, thrown upon fomething as hard, is an effect of their compreffibility. Q. What is a flexible body ? A. It is that whose figure may be easily changed, lengthened, and fhortened, without feparating its parts. Such are the membranes of the bodies of animals, and all the oblong parts of vegetables. Q. What is elasticity? A. It is the effort whereby certain compreffed bodies tend to restore themselves to A. It is a refiftance greater than that of their former ftate. This properly fuppofes foftness. Q. What is hardness? A. It is a refiftance ftill greater than that of firmness. It is faid that a body is hard, when its parts hold together, and cannot be taken afunder without breaking. that they are compreffed. Of all bodies of this fort, fome remain in the state of their compreffion, as a ball of lead, that remains flat after its fall, and a ball of fnow, that remains in the form the hands have given it; others, on the contrary, reftore themselves, and and refume, after being compreffed, the fame dimensions and figure they had before they were fo. Q Are all bodies equally elastic? A. No; fome hardly restore themselves, and then their elasticity is confidered as nothing in ufe. Thofe in which an elaftic force is perceptible, re-act more or less, according to the hardness, stiffness, or difpofition of their internal parts; but we have no pofitive proofs that elasticity is perfect and unalterable in any one; we frequently obferve that this quality is loft or debilitated by long exercife, or by a compreffion that has lafted too long. A bow, which is too long, or too often bent, keeps at last the curvity it has been made to affume. Q. Why is there no perfect elasticity? A. The reafon is this: When a bent body is flackened, fome of its folid parts, that touch each other, must be repelled, and retire, and thus must suffer a confiderable friction, which produces a violent obftacle as to motion, and destroys a part of the force of elafticity. The bodies that have the leaft pores, that are the best polifhed and moft folid, are perhaps thofe that have the greatest elafticity, because they are then lefs fubject to the effects of friction. But there are no compound bodies without pores. The more metals are beaten, the more they become compact and elaftic Their pores are made fmaller by beating them, and even their number is diminished. Tempered fteel is much more folid and elaftic than untempered, and the fpecific weight of the former is to that of the latter as 7809 to 7738. Q. Why is a body more elastic when cold than hot? A. Because its parts are then more clofe, more compact, and more folid. Cold contracts, heat dilates and rarefies them. Q. Of what ufe is the elasticity of bodies? A. Of infinite ufe, whereof a few examples will be fufficient. If it be useful and commodious to travel at eafe, this advantage is chiefly owing to the plates of steel, the bands and fprings of copper, and other elaftic bodies, on which the vehicles are fufpended. The measure of time is fo interesting a thing to all people, that there are few without a watch or clock, which they regard as a neceffary piece of furniture. Thefe forts of inftruments, which may justly be reputed the mafter-pieces of art, are animated by a fpring, formed out of a plate of steel, rolled on itself, in a barrel, which it makes to turn by expanding itself, and whofe motion is communicated by indented wheels to the pivots that bear the hands or indexes for fhew ing the hours and minutes on a dial-plate, divided for that purpofe.. It is fufficient to obferve here, that the action of elafticity has been brought to the perfection of being almost equal during the whole time of difplaying itself; for a difficulty at first prefents itself, which is, that, as the action diminithes always in proportion as the fpring unbends, fo the motion ought alfo to be flower in all the pieces it animates, and the hands ought to make the hours and minutes longer towards the end than the beginning. How ferviceable, in like manner, are the fprings of guns! By what other. means could be operated fuch prompt motions, and so difficult to be perceived by a bird, which nature has put on its guard against every thing that threatens its life? The fnap-haunce, moved by the spring, carries in a moment a fharp flint against finall piece of tempered fteel; the powder catches fire; and the hot it drives forth ftrikes the animal before it can be apprifedby the flash or report, or at least before it can fecure itfelf by this warning. Means have been alfo found to create elafticity, or augment it in bodies which have little or none. All fonorous bodies ought to be elastic; and it is therefore that bells are made of tin and copper melted together, because it has been obferved, that a mixed' metal is more hard, ftiff, and elaftic than the fimple metals it is compofed of. The greater part likewife of metals, without being allayed, become capable of a greater reaction when beaten cold. But, of all bodies whofe elafticity may be artificially augmented, not one is more remarkable than iron converted into steel; and, among the different proceffes for this purpose on that metal, nothing is comparable to tempering. To temper fteel is to cool it fuddenly, the moment it is taken red-hot out of the fire; and this is ufually done by plunging it in cold water, or in fomething equivalent. Q. What is cohefion? A. It is that property of bodies which makes their parts oppote a feparation, whatever may be the caufe of their union. The more the cohesion of the parts of a body is ftrong, the more that body inclines to perfect hardne's. There are many obfcurities in regard to the cohesion of the parts of bodies: According to the Newtonians, the cohefion of parts proceeds from their at tractive virtue. It is, fay they, by this vir tue, that bodies laid upon one another hold faft together. The more their furface is fmooth and polished, the more their cohefion is ftrong: But this cohefion is the lets ftrong, ftrong, when their furface is craggy and uneven, because they then touch only in a fmall number of points. Q. What is the fluidity of bodies? A. A body is faid to be fluid, when its parts yield to an impreffion, and that in yielding they move with great facility. We fhall hereafter fpeak more particularly of fluids. Q. What is understood by the confiftence or fixity of bodies? A. That ftate whereby their conftituent parts keep naturally the fame pofition in regard to one another, and cannot without difficulty be detached or feparated. Q. What is the thinnefs of bodies? A. Thin bodies are called those that have a lax ftructure, and occupy a great space under a small folid mafs. Bodies are more or lefs denfe, more or lefs thin, according to the bignefs or fmallnefs of their pores. Q. What are tranfparency and opacity? A. Tranfparent or diaphanous bodies are thofe through which objects may be feen; fuch are glafs, crystal, &c. Opaque bodies are thofe through which objects cannot be feen. In transparent bodies the rays of light may pafs freely through their porcs, whereas they are ftopped in their paffage through opaque bodies. Of the VIS INERTIÆ, or PASSIVE FORCE. Q. What is the vis inertiæ, or paffive force? A. It is that refiftance against motion perceptible in all bodies. Q. How may we form fome notion of it? A. Nothing feems more proper for that purpofe than the experiment propofed by Sir Ifaac Newton: Let a body be imagined of a determinate weight and bignefs; for inftance, a bowl of lead, weighing a pound, suspended freely by a very long thread, in a T calm air, and another like bowl of lead, fuf pended in the fame manner, and striking against the firft, with four degrees of motion. If the bowl at reft made no refistance against that which strikes it, after the fhock both would be feen to move with four degrees of motion: For why fhould motion be diminished in the bowl that ftrikes, if there was no refiftance in that which is ftruck? And for what reason should not the bowl be difplaced according to the whole extent of the motion that drives it. But experience fhews otherwife: The bowl at reft receives from that which ftrikes it a portion of its motion, and the latter lofes in the fhock what the other feems to have acquired. A body at reft makes therefore a real refiftance against the effort that tends to move it. There is ftill more; if the bowl at rest weighs 30 or 40 pounds, the other, which has then but a much lefs mats, with the fame effort, does not drive it as far as in the foregoing cafe; yet, if, to move a body, it was only required to make it lofe its ftate of reft, the motion communicated would be the fame in a large as in a small mass. There is therefore fomething more to conquer than the mere privation of motion; and that to be conquered is the resistance called vis inertiæ, or paffive force. Q. Is this force alfo found in fluids? A. Yes; because it does not depend on the folidity of parts. It is as great in a cubic foot of water, as in the fame water changed into ice. Q. Does it depend on weight? A. No; because it acts equally in a body, whatever direction is given it, and even when fituated horizontally. is? Q. Can we know exactly what this force A. It is one of the things we are ignorant of, and which we perhaps hall never know. OCCASIONAL LETTERS. LETTER LXXVIII. True PLEASURES are rendered the purer by a moderate Ufe of them. Not to turn human brutal, but to build O know how to moderate our defires, is going a great way in the path which leads to true happiness. The generality of men pass their lives in wishing for what they cannot obtain; or, if they obtain that wish, they prefently form new ones: Their hearts are fwelled with more defires than there are waves on the troubled ocean; fome are confu'ed, others hurtful, fome horrid and deteftable; fome are ridiculous and fenfeless, YOUNG'S Night Thoughts. while there are others conformable to reafon and virtue: In fine, there is nothing, that is either allowable or criminal, but what is by turns the object of mens wishes. To expect that a man fhould have no defires, is the fame thing as to require him to cease to be man; for there are many defires which are effential to his natural exiftence. Thefe do no prejudice to his happiness, but on the contrary tend to his prefervation, and inftruct |