regulation of projects made in the air with very fwift motions, and that it must be proper experiments only which can lead us to the true useful rules for practice, by investigating the effects of the refiftance of that medium; and that in order to this, the intensity of the first moving force, or fired gunpowder, must be actually determined. He then fhews that we had no experiments of this kind to lead us to any useful difcovery, before thofe of the very ingenious Mr. Robins, nor even fince, except fuch as have been made after his manner, and particularly those that are related in Mr. Hutton's paper, which gave occafion to this difcourfe. He afterwards defcribes the nature of thofe experiments, and wherein Mr. Hutton's differ from and are improvements on those of Mr. Robins, in this manner:

• Much therefore are we indebted, fays he, to Mr. Hutton, who, treading in the footsteps of the deceafed, hath refumed and profecuted this laft defideratum, and hath fhewn himself not un equal to fo difficult an enterprize.

Mr. Robins, for determining the initial velocity of hot, arifing from different quantities of powder, made ufe of balls of about an ounce weight; whereas Mr. Hutton, tor the fame purpofe, hath employed thofe of different weights, from one pound to nearly three; or, in other words, Mr. Robins made trial with mufket-fhot only; Mr, Hutton with cannon-balls, from 20 to about 50 times heavier. This was a confiderable ftep gained in a difquifition on that part of the fcience, in which the refiftance of the air and other circumstances were not concerned and where neither analogy alone, nor mathematical deductions alone, nor the two combined, were fufficient for establishing principles applicable to the motion of cannon-balls, without making a new feries of experiments and with what labour and judgement thefe have been performed, you understood by the account which Mr. Hutton gave of them in his paper.

• But should it now be inquired, what advantages may be derived from Mr. Hutton's experiments, for the advancement of the art of gunnery, and of philofophy in general? I would reply, that as to the former it may be fufficient to obferve, that though the improvements be only fuch as can be deduced from the force of fired gun-powder; yet they are in a higher, more certain, and in a more general manner, than what refulted from the labours of Mr. Robins; who indeed led the way, but who made, as it were in miniature, thofe experiments which Mr. Hutton hath executed at large, and which Robins himself wished to have made, as well as others who have confidered the fubject fince his time. Now thefe experiments, though made by Mr. Hutton with cannon-balls of a fmall fize, may neverthelefs form juft conclufions when applied to cannon-fhot of the largest fize. And fuch conclufions inform us of the real force

of powder when fired, either in a cannon or a mortar, impelling a bail or bomb of a given weight; that is, they discover with what velocity a given quantity of powder drives thofe projectiles in a fecond, or in any other affigned portion of time. They alfo fhew the law of variation in the velocity arifing from-dif. ferent quantities of powder, with the fame weight of metal, and likewife that law which takes place upon ufing balls of dif ferent weights. Further, they point out the advantage obtained by diminishing the windage in cannon, and teach us how we may increase the weight of the fhot in the fame piece, by making it of a cylindrical form, inftead of a fpherical: by this device, a fmaller fhip may be enabled to do the execution of a larger one. And experiments of the fame kind will alfo determine the just length of cannon for fhooting fartheft with the fame charge of powder.

Laftly, it is from thefe experiments, or from others that may be made after the like manner, we are inftructed how to anfwer every queftion relative to military projectiles, except fuch as depend on the refiftance of the air to bodies moving fwiftly in it. This indeed is a confideration which leaves room for greater improvement in the art, and for conferring fresh honours on thofe, who, like Mr. Hutton, fhall have opportunities and abilities for continuing and perfecting this very curious and ufeful inquiry.

1

As to the advantages accruing to philofophy from the labours both of Mr. Robins and Mr. Hutton, fpeak they not for themselves? The fciences of motion and pneumatics are promoted by them; and of what avail their perfection would be for the farther interpretation of nature, you need not be informed. In fine, we have here before us, in thefe experiments, the fureft teft of our advancement in true knowledge, which is, the improvement of a liberal art, and the enlargement of the powers of man over the works of creation.'

To obviate an objection which very naturally arifes, fir John then adds,

• Some however may think, that the objects of this Society are the arts of peace alone, not thofe of war, and that, confidering how numerous and how keen the inftruments of death already are, it would better become ut to difcourage than to countenance their farther improvement. Thefe naturally will be the first thoughts of the beft difpofed minds. But when upon a closer examination we find, that fince the invention of arms of the quickest execution, neither battles nor fieges have been more frequent nor more defiructive, indeed apparently otherwife; may we not thence infer, that fuch means as have been employed to fharpen the fword, have tended more to diminish than to in crease the number of its victims, by fhortening, contefts and making them more decifive. I fhall not however infilt on maintaining fo great a paradox; but only furmife, that whatever

ftate

ftate would adopt the Utopian maxims, and profcribe the ftudy of arms, would foon, I fear, become a prey to those who beft knew how to use them. For yet, alas! far feem we to be removed from thofe promised times, "when nation fhall not lift up fword against nation, neither fhall they learn war any

more !"

Having thus finifhed this excellent Difcourfe to the largest audience that perhaps was ever affembled at the meetings of this learned and refpectable body, fir John then ended the bufinefs of his office of prefident by prefenting Mr. Hutton with the medal, pronouncing to him at the fame time the foilowing words:

You have heard, fir, the account I have given of the rife and progrefs of the theory of gunnery, and of your improvement of it; a recital, which by no means would have done either you or the fubject justice, had it been addreffed to any other audience than to the prefent. But as my intention was only briefly to recall to the memory of thefe gentlemen what they knew of this fubject, antecedently to your paper, and to remind them of the refult of your experiments, I flatter myself 1 have faid what was fufficient on the occafion: being now authorized by them to deliver into your hand this medal, as the perpetual memorial of their approbation. And let me add, fir, that they make you this prefent with the more cordial affection, as by your other ingenious and valuable communications they are af fured, not only of your talents, but of your zeal, for promoting the interefts and honour of their inftitution."

Gulftonian Lectures read at the College of Phyficians, February 15, 16, and 17. By Samuel Mufgrave, M. D. 800. 25. Payne.

TH

HE firft of thefe Lectures treats pathologically of the Dyspnoea, in confidering which the author diffents in fome points from the theory of baron Haller. This diversity of opinion relates to a particular state of the respiratory organs, which Dr. Mufgrave diftinguishes by the name of obstructed expiration. It exifts when the abdominal muscles act with great power to expel the breath, at the fame time that the egrefs of the latter is prevented, either by a conftriction of the glottis, fometimes voluntary and fometimes convulfive, or elfe by a strong effort of the buccinator mufcles confining it within the cavity of the mouth. This ftate of the refpiratory organs is obfervable when a perfon attempts to lift a heavy weight. It is imagined by Haller to confift in a long infpiration, accompanied with a great defcent of the dia

phragm;

phragm but Dr. Mufgrave, on the contrary, fuppofes, that the diaphragm, inftead of being contracted fo as to form a at furface, is forced up by the power of the abdominal mu cles, fo as to form a furface of confiderable convexity towards the thorax: His reafons for this opinion are, firft, becaufe the power of the abdominal muscles is confiderably greater than that of the diaphragm. Secondly, if the diaphragm was strong enough to withstand the action of the abdominal muscles, and did really withstand it, the conftri&tion of the glottis, or the fhutting of the lips, would be a matter of indifference, as the air contained in the thorax fuffering no preffure, would be in no danger of escaping. As we find therefore, fays he, that in all muscular efforts, either the glottis or the mouth is closely fhut, we may reasonably infer that it is fhut to prevent the efcape of the air contained in the thorax ; confequently that this air is preffed upon from beneath by the convexity of the diaphragm.

In the third place, Dr. Mufgrave obferves, if we suppose with baron Haller, that in all mufcular efforts the diaphragm defcends and enlarges the cavity of the thorax, it will be im poffible to account for the obftruction fuch efforts give to the circulation of the blood through the lungs, and for the confequent accumulation of it in the right auricle and ventricle, the vena cava, and the jugulars; an accumulation ftrongly in dicated by a variety of symptoms.

The fecond Lecture is employed on the Pleurify and Peripneumony, in the treatment of both which diseases the author approves the practice recommended by Sydenham, more than that of any other writer; and he imputes the frequent unsuccessful attempts of curing those disorders to a neglect of the cautions delivered by that celebrated phyfician. One of these relates to the injunction of taking the patient out of bed every day, for the fpace of feveral hours if his ftrength will admit of it; as in all inflammatory difeafes, the warmth of the bed is found to have an exceeding bad effect.

I know not, fays our author, whether I fhall be pardoned, for fuppofing that the direction of fo celebrated a practitioner has not been fully or properly attended to; but fure 1 am, there is but too much ground for the fuppofition. I do not infer this from having heard little of it in converfation, fince every man's acquaintance is confined within a comparatively small circle; but I collect it from this moft remarkable circumftance, that almost all the writers upon the pleurify and peripneumony, from the time of Sydenham to the prefent hour, have paft it over in filence. There are, it is true, fome few exceptions. Boerhaave hints at it, but fo flightly, that it is plain he laid no great

Arefs

refs upon it. Van Swieten mentions it exprefsly, and com mends it, but without faying that he had ever seen the good effects of it; from which, as he is by no means fparing of words, I conclude he had never practifed it. De Haen makes it a general rule in all fevers, to take his patients out of bed, and even to keep them in an erect pofture for feveral hours. The practice of taking them out of bed, if confined to the peripneumony and other inflammatory fevers, would have done him great honour; but he has loft the merit of it, by extending it to thofe of the nervous and malignant kind; which, to say the leaft of it, is unfafe, and when combined with that other injunction of an erect pofture, becomes particularly abfurd. Van Swieten excepted, Dr. Cullen comes the nearest to Sydenham of any author, that has fallen in my way; and even he seems to think, that lying in bed under a light covering is nearly equivalent to being taken out of it.

But the writers who have totally difregarded this precept, are much more numerous, and fome of them equally eminent. Baglivi, who was no ftranger to the works of Sydenham, upon the fubject now before us, which however he has very copiously treated, does not feem to have looked into him at all. TrilJerus, a celebrated phyfician in Germany, who has written an entire book upon the pleurify, enters into a minute defcription of the beds proper for the fick; but fays not a word of taking them out of it. His countryman Werlhof, who mentions the pleurify incidentally, objects to their being removed ex lecti tepore, even for the purpose of going to ftool. Dr. Huxham, my predeceffor at Plymouth, has written three long chapters, one on the peripneumony and pleuro-peripneumony, a fecond on the peripneumonia notha, and a third on the pleurify; all which fubjects he has treated with fuch a laborious and minute exactness, as if no fymptom or rule of practice could poffibly have escaped him. Yet in this very prolix difcourfe, containing, perhaps, every thing elfe that the argument could fuggeft, there is not one word or fyllable relative to what Sydenham confiders as effential to the fuccefsful treatment. I could name also authors, hot a few, of our own age and country, men of confiderable reputation, and even eminence, who have written profeffedly upon the pleurify, and all been equally attentive to this circumstance. What shall we fay, what caufe can we affign for fuch a fingular omiffion? If we confider the authority and reputation of Sydenham, and the very pofitive and striking manner in which this aphorifm is delivered, it is difficult to conceive that fo many writers fhould have paffed it over with deliberate contempt. Yet if we reject this fuppofition, we are obliged to fuppofe what is ftill more harth, that in confulting this part of Sydenham's book, they had only caft their eye upon the beginning of the chapter, and not taken the trouble of reading it to the end,

• A re