Sir James. Are they therefore entitled to give the alarm, when no fuch defign is intended? Sir Robert. By no means. A pack of factious, infamous fcoun drels. Margin. It is we that fupply the defects of the laws. Sir James. You! Margin. By fligmatizing thofe offenders that they cannot reach. Sir James. And is a pretence for making the innocent the butts of their malice. Sir Robert.. True, true, all is fifh that comes to their nets. Sir James. Befides, their flander is fcattered fo generally, and with fo little difcretion, that the deformity of vice is deftroyed. Sir Robert. True. Sir James. Bad men are made worfe, by becoming totally callous, and even the good rendered careless, to that fource of patriotism, that pride of virtue, the public opinion. Sir Robert. And they are much in the right on't. Margin. What, you are a courtier, I reckon? no wonder you wifh the prefs was demolished. Sir James. If ever that happens, to fuch miscreants as you 'twill be owing; nor will it furprize me, if all orders concur to give up a great public benefit, for the fake and fecurity of private honour and peace. Thefe laft reflections, to which the fubject naturally led, are indeed as melancholy as they are juft; nor will it be any wonder if while the age grows callous to reproof, fome future adminiftration fhould take advantage of the licentiousness of the press to deprive us of its liberty.-Yet all this, we fay again, comes with a very bad grace from Mr. Foote, who has not only abused the prefs but the stage, as much as any man living, by the moft wanton and cruel instances of personal fatire. It is befide particularly ungrateful to his ftaunch little friend, the doer of a certain Morning Chronicle, who in behalf of his favourite Arifto. phanes, ungratefully abuses his best friends and benefactors; appearing determined to flick by his brother ftroller in all times and circumstances, till the very dirt by which he sticks be washed off, and the Æthiop become fair as alabaster, Amen! W. A Survey of Experimental Philofophy; confidered in the prefent State of Improvement. Illuftrated with Cuts. 2 vol. 12's. Carnan and Newbery. In an age, when the manner, instead of the matter, of literary publications, is held chiefly in eftimation, it is no wonder if profeffed writers, of an easy and happy turn of expreffion, should be preffed into a fervice; which they never would have enlifted ander as volunteers. We would wish at least, to impute, to mo 1 tives of felf-intereft rather than to thofe of felf-fufficiency, the late Dr. Goldsmith's undertaking a Survey of Experimental Philo sophy *. Not but that this ingenious writer might plead illuftrious precedent in the example of Voltaire! who, after attending a week or two on the lectures of 'sGravefande at Leyden, fet up for an illuftrator of the whole fyftem of Newtonian Philofophy. To do him juftice alfo, it must be owned that, so far as the pupil had profited by the preceptor in comprehending the subject, his illuftrations had infinitely the advantage of ftile and diction over those of most other writers. In this refpect too the parallel will hold good between Dr. Goldsmith and Voltaire. We are apprehenfive, likewife, it will be justly carried ftill farther; and that notwithstanding the propriety and perfpicuity of expreffion, which is generally prevalent throughout the whole, the poet will be frequently found to have run away with the philosopher, and to have fubftituted the dazzling brilliancy of imagination for the clear elucidation of fact. While we recommend this performance, therefore, as the best-written and most familiar treatife, our language affords on the fubject, our duty, as impartial Reviewers, compels us to point out fome of thofe paffages, in which, the author appears, from inattention or misapprehenfion,, to have rather confufed than illuftrated the matter in difcuffion. We are the more indispensibly obliged to this, as we are told, in a prefixed advertisement, that the reader will find his account in the perufal of the work, by meeting with fome things new and uncommon, not unworthy of the author, nor the attention of the Public. On the cafual opening of the fecond volume, appears a striking inftance of forgetfulness and mifrepresentation of a very familiar. and common topic. This is our author's defcription and illuftration of the ufe and application of that well-known inftrument the Thermometer †. "The thermometer now used most frequently, is that of Fahrenheit's improvement. The fluid with which the bulb at the bottom is filled, is mercury; upon the fide of the tube are marked the divifions at which the fluid expands by different degrees of heat from freezing, which he calls the freezing point, up to the greatest heats fluid fubflances are capable of receiving. Thus when we fay, human heat is ninety-eight degrees by Fahrenheit's thermometer, it means only this,' that the heat of a man's body is ninety-eight of thofe degrees warmer than water when it begins to freeze. On the other hand, when we are That this work is really Dr. Goldfinith's, and not fathered upon him as fome things have been, there is no doubt. The first volume was printed off in his life-time, and the copy of the whole put into the hands of the publither long before this author's death Vol. II. page 220. are told, that in Greenland the mercury fometimes ftands feven degrees lower than o by Fahrenheit's thermometer, it only implies that the air is feven degres colder than water when it begins to freeze." This is a strange over fight in a profeffed furveyor: the freezing point on Fahrenheit's thermometer is at thirty-two degrees and not at o or the beginning of the fcale; fo that all our author's fine illuftration is thrown away. Numerous, however, are the fimilar inftances we meet with of his apparently mifconceiving and evidently mifrepresenting the moft common and familiar experiments. To cite only two or three. "La Hire and Defaguliers give us several accounts of the amazing weight fome people have fuftained, when they were able to fix the pillar of their bones directly beneath it. The latter tells us of a German who fhewed several feats of this kind at London, and who performed before the King and a part of the royal family. This man, being placed in a proper fituation, with a belt which refted upon his head and fhoulders, and which was fixed below to a cannon of four thousand weight, had the props which fupported the cannon taken away, and by fixing the pillar of his bones immoveably againft the weight, fupported it with feeming unconcern. There are few that have not feen those men, who, catching a horse by the tail, and placing themselves in direct oppofition to the animal's motion, have thus ftopt the horse, though whipped by his rider to proceed •. Now the belt made ufe of in the above experiments did not reft on the head and shoulders, but begirt the hips, refting on the offa innominata, forming an arch of wonderful refiftance. In the affair of the cannon, the man being placed in a wooden frame and ftooping forward, refted the upper part of his body by his hands. on one fide the frame; the rope fupporting the cannon hanging down from his hips: the bony arch covering the pelvis, and the bones of the leg and thigh only fupporting the weight of the cannon †. Again, the bufinefs of a man's catching a horfe by the tail and. ftopping him, though whipped forward by his rider, is equally mifreprefented. The ftrongest man in the world would find it impoffible to catch a horse by the tail, and of then placing himself in fuch a manner as to stop him.-The fact is, that the horse in this cafe, is not fuppofed to be on a full gallop, or in actual motion, as the doctor feems to infinuate; but stands still, while the man, who is to prevent his motion (not to stop him when moving) places himself in a frame with the belt fastened round him in the fame manner as in the former experiment. We would advise the experimentalift to beware of taking these things ftrictly Vol I. page 253. + If we remember right, King George II. who was no robuft man, fupported twelve hundred weight in this manner. ftrictly according to the letter, left he get his bones broke, or his brains dashed out, in the trial. The theorift alfo should be cautious of the inferences he deduces from this method of catching a horse by the tail, left, as the fatirist says," he catch the eel of fcience by the tail" only to let it flip through his fingers. In telling the trite ftory of Archimedes' difcovery of the method of detecting the fraud of the goldfmith in making the crown of Hiero, king of Syracufe, he fays," the resistance he found from the water in going into the bath, gave him the hint of weighing the crown hydroftatically.*" But it was not the refiftance of the water, but its palpable rife on the fides of the bath which naturally fuggefted fuch hint. To cite an instance or two of defective illuftration, and difmifs the article. In explaining the theory of percuffion among elastic bodies, it is faid, "The bodies made use of in fuch admeasurements are ivory balls, which difcover the greateft elafticity. They are hung upon ftrings like pendulums, and then let fall from determined heights, which heights are adjusted by a fcale. The height from which the body falls reprefents its velocity, the weight and height together reprefents the body's force,t" Our experimental furveyor fhould here have mentioned in what manner these heights were adjusted by a scale. For want of this the learner will naturally fuppofe him to mean perpendicular heights; in which fuppofition he will be mistaken. The velocity of a falling body is represented by the square root of the perpendicular height from which it falls; that height being conftantly as the fquare of the velocity gained by the fall. But in pendulums, defcribing arches round a centre, the chord of the fegment bears the fame proportion to the perpendicular height of the afcent, so that the lengths of the chords of the refpective vibrations are the heights here meant. Of the augmentation of force in the percuffion of elaftic bodies, is given the following theory and obfervation. "If a force be communicated from a smaller elaftic body to a larger, by means of feveral intermediate bodies each larger than the other, the motion will be augmented in each of them, and the motion of the laft will greatly exceed that of the firft; and this force will be conveyed with leaft diminution, if the weights of the bodies rife above each other fo that the laft be as much greater than the former, as that is exceeded by the foregoing. As an inflance how prodigiously force may be augmented by being fucceffively communicated through a range of bodies, increafing in this progreffion: If twenty claftic bodies be placed one after another, each fucceeding body being twenty VOL. III. Bb b Vol. I. page 377. + Vol. I. page 204. times The reader may fee this fubject treated with the utmoft plainnefs and perfpicuity in the Lectures of Dr. Hamilton of Dublin, lately jublished. times greater than that next it, and if a force be impreffed upon the fmalleft body, the laft body will fly off with a force two hundred thousand times greater than that with which the smallest body first ftruck the range. If we should fuppofe a cannon ball, fhot from its culverin, to be elaftic, and ftriking with all its force a range of balls, increasing in the proportion above-mentioned; what an amazing effect would it not have. But fuch a fwiftnefs would quickly destroy itself; the ball, from the refiftance of the air to its paffage, would fly into a thousand pieces; for no ftroke that we have an idea of, could equal that with which the air, however yielding it may appear to us, would act upon a body thus violently carried againf it. Now, not to stand upon nicety of calculation, or to object that it is by no means neceffary the cannon-ball itfelf fhould be elaftic, if the series of bodies ftruck are fo, our author here evidently mistakes the nature of the amazing effect which such a stroke of a ball from a culverin would have.-He supposes that, from the prodigious increase of power in the paffage of the motion from the first to the last of a series of elastic bodies thus increafing in weight, the velocity of the motion of the laft would be prodigiously great. But this is an egregious mistake. That the momentum of the motion is increafed in proportion to the increased weight is most certain, but the velocity of that motion is diminished in the fame proportion; so that there would be no fuck amazing swiftnefs of motion generated as is above infinuated. We fay infinuated, for it is not clearly expreffed; the author fpeaking of the ball being dafhed to pieces by the refiftance of the air. Not furely the ball fhot from the culverin! This would not be dashed to pieces by the resistance made to it by the air: and every one of the other balls would be ftill lefs liable to fuch an effect, as they would move proportionably flower according to their increase of weight. : From thefe fpecimens of the inaccuracy with which this Survey of Experimental Philofophy is in many places executed, the rigid mathematician may be apt to condemn the whole; we can affure him, however, that he will find the subject in general treated in that obvious and agreeable manner, which was juftli to be expected from the pen of Dr. Goldsmith. W. An Effay on Glandular Secretion; containing an Experimental Exquiry into the Formation of Pus: and a Critical Examination into an Opinion of Mr. John Hunter's, “that the Blood is alive." By James Hendy, M. D*. 8vo. 25. Bell. That the spleen has an important office, in the animal economy, peculiar to itself is a difcovery, which, Dr. Hendy fays, was * We should have been more obliged to Dr. Hendy's friend, had he fa voured us with a copy of this pamphlet fooner. Its having been little if at all, advertised, was the reason that it has fo long efcaped our notice. |