with the little knowlege which he displays concerning the character of the late Empress and the usual consistency of her mode of acting, when he affirms with so much pathos that she was about to sign the grand document, which was to have decided the contest between England and France, for furnishing 65,000 men immediately to crush the latter, when-mysterious heaven!-she died. On that day or the next, says Mr. E. she was to have signed the document. To this we add, that they who know any thing of Catharine II. know, with certainty, that this document would have been to be signed that day or the next to the day that now is. We agree with our author in censuring those who traduce the memory of the unfortunate Peter III.-but if he had consulted the Life of Catharine in 3 vols. lately published in this country*, he would have seen that ample justice has been done to the memory of that monarch. He is there represented as sensible and humane; and it is there said that he was respected by the people; that he overcame his weakness and indecision; that he signalized his first accession to the crown by acts of beneficence and justice; that he seemed to forget the wrongs which hehad suffered; that he undertook to correct the numerous abuses that had crept into the courts of law; that commerce, the sciences, and the arts, were equally the objects of his attention; that he gave easy audience to all who came, received their petitions, and took the pains himself to see that justice was rendered to them; and that he was continually doing good on all occasions which offered, saying that he trusted in the protection of God alone, and with that he had nothing to fear. There is even a panegyric on him in vol. i. p. 343, 344, &c. Mr. E. says: If Mr. Fox's friend, Mr. Adair, had the interest of his country at heart, and not the removal of Mr. Pitt, why did he not promote the alliance of Russia with Great Britain?" Prince Potemkin knew better than to imagine that Mr. Adair had any powers from England. • Of later events,' says the author, 'I shall not now speak: the situation I have been in might involve me in a censure of breach of confidence.' Mr. Eton, while at Petersburgh, was taken by Sir Charles Whitworth into his office, to assist Mr. Dunant, as his private secretary. This work, notwithstanding its questionable bias, and its inaccuracies in point of diction, may be considered as a valuable supplement to that of Baron de Tott. * See M. Rev. July last, p. 266. ART. ART. VI. Astronomical Observations made at the Royal Observatory at Greenwich, from the Year 1750 to the Year 1762. By the Rev. James Bradley, D. D. Astronomer Royal, Savilian Professor of Astronomy at Oxford, F. R. S. &c. &c. Folio. Vol. I. Oxford, at the Clarendon Press, 1798. Price 51. 5s. in Sheets. Sold in London by Elmsley and Bremner. F our I ur readers consult the Review for April 1796, p. 437, they will find that we there stated fully the case relative to the Observations of the late Dr. Bradley, and animadverted with freedom on the delay which their publication experienced. We are happy in acknowleging that our predictions, or rather our fears, concerning the fate of these valuable papers, have been falsified: since the Observations are now presented to the public, and in a splendid form, more worthy indeed of the magnificence of a great University, than suitable to the use of the practical astronomer. As in our former article we might be supposed to speak the sentiments of those who were offended with the University of Oxford for the slowness of their proceedings, it will be but fair to attend to the justification of Dr. Hornsby, the editor of the present work. He begins his preface with stating and asserting that the blame of the delay, which these Observations have experienced, cannot properly be charged on any of those in whose possession the originals have been since the author's death. These originals were first claimed by the Royal Society; and afterward by the crown, at the instance of the Commissioners of the Board of Longitude. Dr. Hornsby remarks (and, we think, with justice) that it could hardly be expected that these invaluable labours of Dr. Bradley should depart from him in consideration of a small and inadequate salary (901. a-year). He then proceeds to state that, after the lawsuit was abandoned by the crown, (which suit was commenced in 1767 and continued to 1776,) these papers were offered voluntarily by the Rev. S. Peach, who came into their possession by right of his wife the only child of the late Dr. Bradley, to the late Earl of Guildford, then Lord North, Chancellor of the University of Oxford, to be by him presented to the said University. This offer (says Dr. H.) was graciously accepted by his Lordship, and the donation was made to the University; who lost no time in preparing to print the Observations under the care and conduct of the present editor. With how much toil and assiduity he has laboured in the prosecution of this arduous and important undertaking, is well known to many who have seen and can witness it; and the work would have been long ago completed, had it not been unfortunately interrupted by the editor's ill health, owing perhaps, in some measure, to the intenseness of his application. Nor has he since omitted any single day in which it was possible for him to resume his labour. It has been said, that he ought to have resigned the business into other hands, when he found himself unable to go on with it. But his generous employers thought otherwise: nor does it become him to question the propriety of their determination; who, considering his disqualification as temporary only, thought it most advisable that the same person, who had long managed the labouring oar to their satisfaction, should be allowed, if able, the honour of bringing the vessel into the desired port.' Dr. H. having said thus much concerning the causes of the delay, (which, according to him, have been censured with much unjust and acrimonious obloquy,) proceeds to give some account of the instruments used by Dr Bradley. The tables of the present volume are, Tab. Ist. Observed Transits of the Sun, Planets, and Fixed Tab. 2d. Meridional Distances of the Sun, Planets, and Likewise Apparent Right Ascensions. 41 pages. ART. VII. Experimental Essays, Political, Economical, and Philofophical. By Benjamin, Count of Rumford. Essay VII. Of the Propagation of Heat in Fluids. Part II. An Account of several new Experiments, &c. 8vo. 1s. 6d. Cadell jun. and Davies. 1798. IN the preceding part of this essay, which we have already noticed (see Rev. vol. xxiv. p. 319.), the ingenious and respectable writer produced a variety of experiments to prove that water was a non-conductor of heat. In the present publication, we find a few additional experiments to shew that the same law prevails as to oil and mercury; and we have again to admire the accuracy and the simplicity of contrivance which distinguish this philosopher. A cake of ice 3 inches thick, having a pointed projection rising 1⁄2 inch in height from the centre of its upper surface, was frozen in a glass cylindrical jar 44 inches in diameter: fine olive oil, previously cooled to the temperature of 32o Fahrenheit, was poured on the cake of ice till it stood at the height of 3 inches above it. A cylinder of of wrought iron 14 inch in diameter and 12 inches long, being heated to the temperature of 210° in boiling water, was immersed in the oil to such a depth, that the middle of the flat surface of the end of the hot iron, which was directly above the point of the conical projection of ice, was distant from it only of an inch. Agreeably to the expectation of the author, no heat was found to descend through the thin stratum of oil which remained interposed between the hot surface of the iron and the pointed projection of ice; for it did not appear that there was any diminution of the height of this projection, nor any alteration of its form; nor that the ice was in any way affected by the vicinity of the hot iron. A similar experiment, substituting mercury for oil, was then made, and was attended with a similar result. There are other experiments, to shew that radiant heat also does not descend through water, oil, melted tallow, nor melted wax. The principle of all these last-mentioned experiments consists simply in suspending a red-hot bullet above the surface of the substances with which the experiment is made. When ice was used, the quantity thawed was very little, and occupied a small circular excavation of a very inconsiderable depth, but rather deeper at and near to its centre, than at its sides. When tallow or bee's wax was used, the result in one respect was very singularly different; for the surface of the unmelted tallow and wax, instead of being concave, as in the ice, rose up in the form of a protuberance, or very blunt point; the extremity of which reached almost to the surface of that which was melted. From these and the various other trials which the Count has made in the investigation of this difficult and interesting subject, he thinks that he has ground for concluding that all fluids are nonconductors of heat: that is, that heat, in diffusing itself through the mass of a fluid, is not transmitted from particle to particle, de proche en proche, but that the heated particles, becoming specifically lighter by the addition of the heat, rise in the fluid; that, this operation taking place with respect to all the component particles, as they successively come into contact with the heat, the whole fluid mass thus becomes gradually heated; and that, when any substance takes the form of a fluid, all interchange and communication of heat among its particles, or from one to the other, becomes from that moment absolutely impossible. It would be presumption in us to pronounce decisively on the truth and propriety of this conclusion: yet we cannot but think that, in the latter part of it, the author has carried it to an extent which neither his own experiments nor general reasoning on the subject will completely justify; for the power REV. OCT. 1798. N of of communicating and interchanging heat between the particles of a fluid and other substances, and between the different particles of fluids of different specific gravities, is a fact which, we apprehend, the author himself will not controvert; since the rising and falling of the mercury in the thermometer prove the one, and the freezing of water on ice-cold mercury proves the other. If this be true, why then should it be supposed that, in reference to the particles of the same fluid, this power should be lost? The existence of this power does not at all militate against the mode of the propagation of heat maintained by our author; for, supposing it to exist, still his theory cannot be negatived without supposing the suspension of one of the most powerful and pervasive of nature's laws, that of gravitation :-for, if heat diminishes the specific gravity of any body to which it is communicated, and if a less specifically heavy body will rise in another specifically heavier if in a fluid state, would it not be a most flagrant absurdity to suppose that the integrant particles of water, oil, &c. rendered lighter by the addition of heat, will not rise above those particles of the same fluid which are heavier because colder?-but that the operation of gravity should counteract, by anticipating, this power of communication and interchange between the particles might naturally be expected: for it is reasonable to suppose that some continuance of contact, though it would be difficult to say what, between the integrant particles of a fluid, must take place before a heated particle would give off its acquired heat to another; and on the supposition that the velocity acquired by the heated particle, in consequence of the diminution of its specific gravity, should even be so small as that of 1738 part of an inch in one second, and on the supposition that the diameter of an integrant particle is one millionth of an inch, the contact of the particle in motion with any other individual particle not in motion, against which it strikes in its progress, cannot last longer than the 17 part of a second nearly. Though we shall not presume to say that this continuance of contact is not suficient for the communication of heat from particle to particle, still we think that so very short a duration of contact is sufficient to justify us in our opinion, that the power of communication and interchange is probably only prevented by the operation of the law of gravity; in opposition to Count Rumford's idea that this power does not exist. A considerable portion of this pamphlet is occupied with observations on chemical affinity; the existence of which the ingenious author attempts to argue away, on the idea that the mode in which heat is propagated in fluids is sufficient to explain all the phænomena of chemical solution. In support of |