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powers of his voice ; his arms would be elevated, and spread abroad in order to intimate the comprehension of gigantic space. This deIcriptive gesture would be aided by an immediate and spontaneous infation of his cheeks, till his breath would find a passage through his nostrils. This natural description of a huge bulk would produce the found B-M; and that sound, rendered articulate by the intervention of a vowel, would describe bulkiness, * and might be appropriated most bappily to the elephant, or great beast.' p. 382. 383.
In a similar manner, Mr Davies explains the origin of the primitive names, by which Adam exprefled to Eve the horse, cow, sheep and dove. Sios, the Hebrew name of the horse, is formed by a sudden hilig effusion of his breath :' An imitation of the voices of the cow and Sheep, gives them their respective names, mro and ba.
• He may have described the dove by fluttering his hand, so as to intimate the act of the wing in flight, and by repeating the syllable toor loor. He now walks forth, accompanied by the mother of mankind. The elephant presents his enormous bulk; the horse flies over the field; the bem, and the foos, are soon and readily distinguished. They are faluted by the cou, the sheep, and the dove : the mgo, the ba, and the toor, are immediately recognized. How great must have been their joy, to find themselves in possession of a social language !' P. 383.
With this sublime passage we take our leave of Mr Davies, of whom most of our readers will probably think they have now heard more than enough.
ART. XI. An Inquiry concerning the Nature of Heat, and the mode of
its Communication. By Benjamin Count of Rumford, V. P. R. S., &c. pp. 105. From Phil. Trans. for 1804. Part I. The labours of this indefatigable experimentalist have unques
1 tionably rendered some fervice to science, by striking out new paths of observation which forced themselves upon his view, in the course of his random and miscellaneous trials. He has also evinced fome sagacity, and much ingenuity, in applying his experiments to practical uses, insomuch that, although his theoretical conclusions are generally unhappy, his corollanes being derived from his observations of fact, and not from his speculative inferences, may generally be relied on, and have of. ten contributed much assistance to the useful arts of common life. We profess to be of the daily increasing number of those who do not think very highly of Count Rumford's talents as a philosopher; and if our former prepoffeffion required any con
firmation • Mr Davies may find a curious inftarce of the fingular aptitude of this radical io express bulkinefs, in the Meafure for Measure of Shakefpeare, Act II, Scene IV.
and, reducing the whole of the results to one standard, it åppears that the velocity with which the heat passed through the polished surface, is to the velocity with which it.paffed through the fame surface covered with four coats of spirit varnish, as
4,566 to 10,000, (for this is evidently the proportion, though · our author réverses it by mistake in p. 101.); and that the velo
city of its paffage through the plain metal is to the velocity of its parliage through the metal tarnished with smoke, as 5,654 to
10,000. The coating of smoke which produces fo great a dife • ference cannot possibly be more than you of an inch in thickness.
Now, we are forcibly struck, we acknowledge, with the exact coincidence between all these curious experiments, and those of Mr Leslie, as detailed in the fixteenth chapter of his Inquiry into the Nature and Propagation of Heat. The same series of obfervations upon the cooling of hot water through plain and coated vefsels--the same fort of calculations, though certainly much better instituted the fame observation of an uniform increase of cooling or heating, by coats of ifinglass and lampblack, form the prominent features of both inductions. Mr Leslie's experiments, however, are more various and masterly ; his mathematical illustrations and proofs are much more skilful; and, though we are not prepared, in this place, to examine the truth of his remote theoretical deductions, we are fatisfied with the accuracy of his intermediate results, which far exceed those of Count Rumford in their number and generality. The next part of the inquiry now before us, is, however, still more striking, from its coincidence with Mr Leslie, to whom the author has not been able to conceal his obligations, although he has certainly abftained from acknowledging them. '. - He commences his next course of experiments with stating, that he found it necessary word - to contrive an instrument for measuring, or rather for discovering those very small changes of temperature in bodies, which are occafioned by the radiations of other neighbouring bodies which happen to be at a higher or at a lower temperature,' p. Iob. 8. This, too, is the precise object of Mr Leslie's differential therinometer ; and, how far the same end has been attained by limiļar means in the two cases, let the following most singular palfage determine. ,
This inftrument' (fays Count Rumford) which I shall take the li. berty to call a thermoscope, is very fimple in its conftru&ion. Like the bygrometer of Mr Leslie (as he has chosen to call his inftrument) it is composed of two glass balls, attached to the two ends of a bent glass tube ; but the balls, instead of being near together, are placed at a Confiderable distance from cach othet ; and this cube which conacets
them, instead of being bent in its middle, and its two extremities turn ed upwards, is quite straight in the middle ; and its two extremities, to which its two balls are attached, are turned perpendicularly upwards, so as to form each a right angle with the middle part of the tube, which remains in a horizontal position.'
• At one of the elbows of this tube' (continues our author) there is inserted a short tube of nearly the same diameter, by means of which a very small quantity of spirit of wine, tinged of a red colour, is in. troduced into the instrument ; and after this is done, the end of this short tube (which is only about an inch long) is sealed hermetically; and all communication is cut off between the air in the balls of the in. Arument and in its tube, and the external air of the atmosphere.'
He then goes on to explain the application of this instrument, by passing a portion of the liquid into the horizontal tube, and allowing it to remain at the middle joint, in which position it must continue, while the temperature of the air in the balls, and consequently their elasticity, is equal. But if bodies radiating unequal degrees of heat be exposed to the balls, or if one ball be exposed to a hot body, and the other defended from it, then the liquor will recede from the ball exposed to the greatest elevation of temperature, and if a cold body be applied to one ball, the other being defended from its influence, the liquor will move towards this ball, so exposed. All this he illustrates by a figure, and by various explanations. We have described it sufficiently, to prove that the thermoscope is exactly Mr Leslie's elegant instrument, denominated by him, not a hygrometer, as Count Rumford is pleased to say, but a differential thermometer. According to the Count's own Statement, he borrows the whole idea from that gentleman ; yet, with an ardour for discoveries not quite scientific, he talks of it as his own contrivance, and, with his accustomed love of nomenclature, he gives it a new appellation. The changes which he makes upon the structure, are utterly unconnected with the theory of the instrument; but it must be remarked that they impede the performance of the experiment. The figure of the tube is both incommodious, and less adapted to the easy passage of the fluids; while the mode of introducing the liquid by a separate tube is extremely clumsy, and in every way worse contrived than Mr Lellie's method. The use and operation, as well as the whole that is worth any thing in the Count's thermoscope, is precisely Mr Lellie's, to which he thinks fit to say, he has invented one like.' Indeed, Mr Leslie had publifhed a description of his beautiful contrivance in several parts of Nicolson's Journal for the year 1800; and every chemilt was acquainted both with that general form of the instrument, and with its application to the purposes of a photometer, long before the year 1803, when Count Rumford's
firmation (which it certainly did not), he has taken very great pains, in the elaborate performance now before us, to supply a variety of new proofs. This inquiry deserves our serious attention in many points of view : The exact coincidence of the only valuable and original matter which it contains, with the late curious and unexpected experiments of Mr Leslie, throws
a suspicion upon one or other of these authors which the public · have a right to see removed.
The merits of Count Rumford, 100, have been so much a theme of conversation, and have had such an active influence in the fashionable world of science, that it is proper his pretensions should at length be Gifted. But, above all, a paper filled with theoretical matter, abounding in pulses, vibrations, internal mo. tions, and ethereal fluids, deserves to be exposed; the more, be. cause these chimeras are mingled with a portion of induction, and have received the ill-deserved honour of a place in the Phim losophical Transactions. We shall, therefore, enter pretty fully into the subject of this inquiry, and are not without hopes that both Count Rumford and the public may be benefited by the discussion.
We shall consider this paper under its two obvious divisionsthe original experiments which it contains, and, the theories in which these are involved.
I. It is by no means our intention to argue against the originality of Count Rumford, or of Mr Leslie, from the circum. stance of their coincidence in some minute particulars. Each of these writers begins with stating the necessity of previously defcribing his apparatus ; and not only do the chief parts of the machinery cally, but we find them both hitting, at the outset, on the same important experiment, and then describing the effects of this occurrence in opening a wide field of new research, and the eagerness with which they entered this field. Such particu. lars, we are sensible, may constitute merely an, accidental coincidence; and had the limilarity of the two inquiries gone no farther, we certainly should not have made the remark. But if we were to state the opinion with which a review of the whole work has impressed us, we should say that Count Rumford had borrowed Mr Leslie's leading discovery, without completely un. derstanding its nature and extent that he had pursued it imperfectly, and so mixed it up with error and fanciful theory, as to disfigure it, and almost prevent one from recognizing the property. The same inference will probably occur to such of our readers as attend to the following details ; and we hope to make it still more obvious in our review of Mr Leslie's work.
The apparatus at first employed by Count Rumford, consisted of several very delicate and accurate mercurial thermometers, with long .cylindrical bulbs, inserted in cylinders of steel ors brafs, to the whole extent of the bulb. These cylinders were: filled with hot water, and coated on the outside with various. thin substances. The cooling of the water was observed by the Ginking of the mercury, and noted duwn at different times, The ends of the cylinders were sometimes' defended by various bad conductors of heat, as eider-down, varnish, &c.; and first, it was ascertained by various trials, that the descent of the thermometer through any given small number of degrees, was performed in equal times, at all heights and all temperatures of the atmosphere, provided the heights were equally above the temperature of the atmosphere. The interval he generally chose, was that between the fiftieth and the fortieth of Fahrenheit above the temperature of the atmosphere. Although he generally was able to note the descent at small intervals, yet, for the sake of continuity, our author obferves that he' endeavoured to investigate the law of the cooling of hot bodies in a cold fluid medium,' and found reason to conclude that a logarithmic will have its ordinates proportional to the degrees of the thermomè. ter, the abfciffa being taken proportional to the times.' He had, indeed, good reason to draw this conclusion; for Sir Ifaac Newton and Brook Taylor, luckily for Count Rumford, long ago investigated this very law, and recorded the result in the carlier numbers of the Philosophical Transactions, where our author probably found it, and thus may be said to have discovered it. This, however, was the general rationale of the experi, ments first performed: we proceed to the results of the trials themselves...
isinii; "*" alt;ironne One of the cylinders, prepared and filled as above, being coated with thin Irish linen, and the other exposed to the air, bright and polished, without any coating, the times of cooling were repeatedly noted. The covered veffel: cooled from 94o to 84° in 364 minutes--the uncovered in 5'5liminates. Both having at last cooled nearly' to the heat of the atmosphere, they were removed into a warmer room, and the covered inftrument received heat considerably faster than the naked one.. In case the linen might produce this effect by preventing the adhefion of the' dir to the vesel, the experiment was repeated with coats ings of glue and of fpirit -varnish, with the same results only, that beyond a certain number of coatings the passage of heat was not accelerated. For the coating of varnish, black and white lize paint were fubftiráted; and then the tarnish of a candle fame, with the famé'effect. Our"author computes, by an easy calculation, the quantity of heat which paffés through the liges of the instrựment, that is, through the parts compared together; * Vol: 1v. "No.8,. ?? ? Čak