These praises are appropriate and just; and, as coming from so high an authority, they are doubly valuable. We are told by Mr. H. that a large sum of money has been left by the will of a Mr. Baillie, for erecting a monument to Lord Mansfield, and also a certain sum for the best inscription. We do not think that the fame of the noble Earl will derive any addition from the praises of a venal muse. May we venture to suggest that, from the classical pen of the present Archbishop of York, (connected by the ties of friendship with the late Earl, and now allied by the marriage of his daughter to the noble possessor of his fortunes and title,) this "Office of Piety," to use Lord Mansfield's words, would be highly desirable? Mr. Holliday is of opinion that, by whomsoever the epitaph is written, it should peculiarly insist on his Lordship's being the founder and author of the present system of commercial law: yet he immediately afterward introduces, in terms of commendation, a proposed epitaph by Mr. David Rees, in which we are told "of the wisdom of Socrates, the eloquence of Cicero, the harmony of Virgil, and the wit and pleasantries of Horace," all concurring in Lord M.: but in which we find not a word of the founder of the present system of commercial law. We conclude this article with the Bishop of Worcester's delineation of Lord Mansfield's character *, as quoted by Mr. Holliday; which, our readers will observe, principally relates to his conduct in the House of Lords: but which is conveyed in terms so correct and elegant, as to excite a just regret that he has not given a more extended view of the subject: "Mr. Murray, afterwards earl of Mansfield, and lord chief justice of England, was so extraordinary a person, and made so great a figure in the world, that his name must go down to posterity with distinguished honor in the public records of the nation; for, his shining talents displayed themselves in every department of the state as well as in the supreme court of justice, his peculiar province, which he filled with a lustre of reputation, not equalled perhaps, certainly not exceeded, by any of his predecessors. "Of his conduct in the House of Lords I can speak with the more confidence, because I speak from my own observation. Too good to be the leader, and too able to be the dupe of any party, he was believed to speak his own sense of public measures, and the authority of his judgement was so high, that, in regular times, the house was usually decided by it. He was no forward or frequent speaker, but reserved himself, as was fit, for occasions worthy of him. In debate he was eloquent as well as wise, or rather he became eloquent by his wisdom. His countenance and tone of voice *Preface to his Edition of Warburton's Works, 4to. REV. MAY, 1798. E imprinted imprinted the ideas of penetration, probity, and candour; but what secured your attention and assent to all he said was his constant good sense, flowing in apt terms, and in the clearest method. He affected no sallies of the imagination, or bursts of passion; much less would he condescend to personal abuse, or to petulant altercation. All was clear candid reason, letting itself so easily into the minds of his hearers as to carry information and conviction with it. In a word, his public senatorial character very much resembled that of Messala, of whom Cicero says, addressing himself to Brutus, "Do not imagine, Brutus, that for worth, honor, and a warm love of his country, any one is comparable to Messala ;" so that his eloquence, in which he wonderfully excels, is almost eclipsed by those virtues and even in his display of that faculty his superior good sense shews itself most; with so much care and skill hath he formed himself to the truest manner of speaking! His powers of genius and invention are confessedly of the first size, yet he almost owes less to them, than the diligent and studious cultivation of judgement. "In the commerce of a private life ford Mansfield was easy, friendly, and very entertaining, extremely sensible of worth in other men, and ready on all occasions to countenance and patronize it." Mr. Holliday has enriched his work with two pleasing engravings, one from a portrait by J. Baptist Vanloo, painted in the year 1734, in which Mr. Murray is represented in his bargown: the other from a miniature picture in the possession of Dr. Combe, which was taken at an advanced period of life, and is an excellent likeness of the venerable Chief Justice. Tou...t. ART. IX. Philosophical Transactions of the Royal Society of London: ASTRONOMICAL PAPERS. A third Catalogue of the comparative Brightness of the Stars; with an introductory Account of an Index to Mr. Flamsteed's Observations of the fixed Stars contained in the second Volume of the HISTORIA COELISTIS. To which are added several useful Results derived from that Index. By William Herschel, LL. D. F.R.S. The index to which Dr. H. refers, and which is likely to be of considerable utility to him in his future researches, was constructed by his sister, according to his direction. It is a work that required time and labour; and we have no doubt of its having been executed with attention and correctness. By means means of this index, the formation of which it is needless to describe, the British Catalogue is easily compared with the observations on which it is supposed to be founded; and it may be determined, whether the stars that are inserted in this catalogue were actually observed by Mr. Flamsteed or not, and likewise what stars, that were either partially or completely observed, have been incorrectly inserted or wholly omitted. It appears that between 5 and 600 stars, observed by Flamsteed, were overlooked when the British Catalogue was framed; and a catalogue of these stars is drawn up by Miss Herschel, who hopes that it may prove a valuable acquisition to astronomers. Dr. H. avails himself of this index, and of his sister's catalogue, in his additional notes to his first catalogues of the comparative brightness of the stars, as well as in those that relate to the third catalogue now published. It is scarcely requisite to add that these catalogues, with the remarks annexed to them, will be extremely useful to those observers, who wish to obtain an accurate acquaintance with the heavens; and that they will serve to direct and determine the inquiries of future astronomers with regard to many stars, of which the magnitude, lustre, and situation, might otherwise be doubtful. Observations on the changeable Brightness of the Satellites of Jupiter, and of the Variation in their apparent Magnitudes: with a Determination of the Time of their rotatory Motions on their Axes. To which are added, a Measure of the Diameter of the second Satellite, and an Estimate of the comparative Size of all the four. By William Herschel, LL.D. F.R.S. The observations recited in this paper were made in 1790, 1794, and 1796. Before he proceeds to draw any conclusions from them, Dr. H. premises some general remarks, in order to prevent the deception to which they are liable, and to facilitate the application of them to the purposes for which they were made. From the very considerable changes that take place in the brightness of the Satellites, it is justly inferred that they have a rotatory motion on their axes, of the same duration with their periodical revolutions about the primary planet. From the unexpected but very observable change in the apparent magnitude of the Satellites, the author concludes that their bodies are not spherical, but of such forms as they have assumed by their quick periodical and slow contemporary rotatory motions, and which forms in future may become a subject for mathematical investigation; or it may denote, in case geometrical researches should not countenance a sufficient deviation from the spherical form, that some part of the discs of these Satellites reflects hardly any light, and therefore in cer E 2 tain tain situations of the Satellite makes it appear of a smaller magnitude than in others.' In order to verify the conclusions deduced from this principle, Dr. H. throws the observations of each Satellite into a graduated circle: but to transcribe his manner of doing it would require a diagram, and lead us into a detail that would far exceed our prescribed limits. Having formed his figures, he deduces his inferences from them almost by mere inspection. The first Satellite revolves on its axis in 14 18h 26', 6. The second in 3 18h 17,9. The third in 7 3 59, 6. The fourth in 16 18 5, 1. From the different tints observed in the fourth Satellite, which appeared dusky, dingy, inclining to orange, reddish, and ruddy, at different times, Dr. H. is induced to surmise that this Satellite has a considerable atmosphere. In estimating the diameter of the second Satellite, by means of its entrance on the disc of the planet, h The duration by the observation is fixed at 4 minutes; in which time it passes over an arch in its orbit of 16′ 52", 9. Now as its distance from the planet is to its distance from the earth, so is 16′52′′,9 to the diameter of the Satellite; or the mean distance of the 2d Satel lite may be rated, with M. de La Lande, at 2′ 57′′ or 177". Then putting this equal to radius, we shall have the following analogy. Radius is to 177" as the tangent of 16' 52", 9 is to the angle, in se.conds, which the diameter of the second Satellite subtends when seen from the earth. And by calculation this comes out o", 87; that is less than nine-tenths of a second.' By this process, it is demonstrated that the diameter of this second Satellite is less, by one half at least, than, from the result of the measures of former observers, it has been supposed to be. From the different expressions which are given of the apparent magnitudes of the Satellites, Dr. H. concludes that the third Satellite is considerably larger than any of the rest; that the first is a little larger than the second, and nearly of the size of the fourth; and that the second is a little smaller than the first and fourth, or the smallest of them all.' PHILOSOPHICAL PAPERS. Experiments to determine the Force of fired Gun-powder. By Benjamin Count of Rumford, F. R. S. M. R. I. A. There is scarcely a subject that has been submitted to the rest of experiment, concerning which the most approved writers have differed so much as the explosive force of gun-powder. Mr. Robins, who has done more towards perfecting the art of gunnery than any single individual, states this force to be 1000 times greater than the mean pressure of the atmosphere; while the celebrated Daniel Bernouilli determines it to be not less than than 10,000 times this pressure. This difference of opinion led Count Rumford to pursue a course of experiments, of which some were published in the 71st volume of the Transactions*, and others are now before us, with the view principally of determining the initial expansive force of fired gunpowder. By an experiment communicated on a former occasion, it appeared that, calculating even on Mr. Robins's own principles, the force of gun-powder, instead of being 1000 times, must at least be 1308 times greater than the mean pressure of the atmosphere. From this experiment, the Count thought himself warranted in concluding that the principles assumed by Mr. Robins were erroneous, and that his mode of ascertaining the force of gun-powder could never satisfactorily determine it. Despairing of success in that way, he resolved to make an attempt for ascertaining this force by actual measurement; and after many unsuccessful experiments, he was at length led to conclude that this force was at least 50,000 times greater than the mean pressure of the atmosphere. It is impossible to account for so great a difference, without supposing that there is some fundamental error in the principles. on which the experiments are conducted, or inaccuracy in the experiments themselves; and it must occur to any person who reflects at all on the subject, that a single experiment is not sufficient to determine a point concerning which such very discordant sentiments have been adopted. We cannot forbear to express our concern that, in the present case, the experiments cited in this paper, though performed under the direction of Count R., in whose judgment we repose great confidence, were not likewise, even in the minutest circumstance attending them, subject to his inspection. We have no reason for questioning the attention and accuracy of the gentlemen by whom they were conducted, nor the fidelity of their report: but, in admitting a conclusion so very different from that deduced from other experiments, not less judiciously conducted and faithfully reported, we cannot but hesitate, and wish for every kind of satisfaction that diversified experiments can afford, and that the importance of the subject in dispute demands. It should be considered, however, that Count R. possessed peculiar advantages, from his situation both in the navy and army, and from continued and indefatigable attention to the object which he had in view, for devising and executing experiments. of the most decisive and satisfactory kind. We are fully convinced that these experiments sufficiently exposed the fallacy of several of the principles assumed by Mr. Robins, and that they Vid. M. Rev. vol. lxvii. p. 123. E 3 furnish |