not this imperfection, and yet her own brother had the like impediment with himfelf. This is fomewhat fingular; unless his father and mother were related to each other before marriage, One of his fifters knows colours, the other does not; the laft has two fons who have this imperfection, and a daughter who is free from it. His own fon and daughter know all colours without exception. Article 40. Defcription of a maft effectual Method of fecuring Buildings against Fire, invented by Charles Lord Viscount Mahon, F. R.S. As it is impoffible to abridge this interefting Article; and as the noble inventor has not in it explained the principles on which bis method is founded; we fhall confine ourselves to his account of two trials of it, made in the prefence of the Prefident and fome of the Fellows of the Royal Society, the LordMayor and Aldermen of London, feveral of the foreign minifters, and others, The lower room of a building, which was about 26 feet long, by 16 wide, was filled with fhavings and faggots, which were fet on fire. The heat was fo intenfe, that the glafs of the windows was melted, like fo much common fealing-wax, and run down in drops; yet the flooring boards of that very room were not burnt through, nor was one of the fide timbers, floorjoifts, or cieling-joifts, damaged in the finalleft degree; and the perfons who went into the room immediately over the room filled with fire, did not perceive any ill effects from it whatever; even the floor of that room being perfectly cool during that enormous conflagration immediately underneath." To reprefent a timber-built town on fire, and to fhew how effectually even a wooden building, fecured in this manner, would ftop the progrefs of the flames; a kind of timber building (of full 50 feet in length, and of three stories high in the middle) had been erected, quite close to one end of the fecured wooden house. The former was filled and covered with above 1100 large kiln faggots, and feveral loads of dry fhavings; and the whole pile was fet on fire. The event is thus related: The height of the flame was no less than 87 feet perpendicular from the ground; and the grafs upon a bank at 159 feet from the fire was all fcorched: yet the fecured wooden building, quite contiguous to this vaft heap of fire, was not at ali damaged, except fome parts of the outer coat of plafter work.'An attempt was next made to burn a wooden ftaircafe, fecured according to the inventor's method: but it refifted the flames, as if it had been conftructed of fire-ftone. Since this experiment, five other, ftill ftronger, fires have been made on and under it; the whole fpace having been filled with fbavings E 2 fhavings and large faggots: but this Afbeftine ftair-cafe is ftill ftanding, and is but little damaged. The noble Inventor of this method propofes, in a short time, to give the world an account, in detail, of many other experiments on this important fubject; and of the application of his method to different kinds of buildings, and to the different conftituent parts of a houfe. He means likewife to add a full explanation of the principles upon which it is founded, and the reafons for its certain and surprising fuccefs. Article 50. Track of his Majesty's armed Brig, Lyon, from England to Davis's Streights, and Labrador, &c. By Lieutenant Richard Pickerfgill, &c. This Article is digefted in a tabular form, and contains the daily obfervations made for determining the longitude by the fun and moon, the error of the common reckoning, the variation of the compafs, dip of the needle, &c. as obferved during the voyage in 1776. At the end of the paper, the Author, without meaning any perfonal reflection,' animadverts on the accounts given by others of this part of the world, fo little known, and fo terribly reprefented.'- Having heard fuch dreadful ftories of thefe countries,' he adds, I cannot help remarking it, as a circumftance equally foblifh and ridiculous; tending to mislead thofe who, from a laudable principle, would be benefactors to their country, but are deterred from it by fuch reprefentations--and he declares his intention of publishing, in a fhort time, his obfervations on the ice, the atmosphere, the land of Forbisher, and the probability of a North-west paffuge *. The remaining papers in this volume are-Article 28. Containing an Account of Baptifins, Marriages, and Burials, during 40 Years, in the Parish of Blandford Forum, Dorfet; by Richard Pulteney, M. D. F. R. S.; where it appears that, on an average, there only dies 1 in 39 yearly.-Art. 30. Aftronomical Obfervations made in the Auftrian Netherlands, in the Years 1773, 1774, and 1775; by Nathaniel Pigott, Efq; F. R. S. &c.-Art. 34. An Account of the Blue Shark, together with a Drawing of the fame, by W. Watson, jun. M. D. F. R. S.— Art. 35. A Defcription of the Exocatus Volitans, or Flying Fish; It is to be feared that we fhall have no more of thefe papers: Mr. P. lately lost his life by the overfetting of a boat on the Thames, as he was going on board a privateer, of which he had the fcommand. The mention of this accident, naturally fuggets to us the melancholy idea of a fill greater lofs which the public hath fuftained by the unfortunate death of, perhaps, the greatest navigator that ever exited: Need we add the celebrated name of Capt. Cook ?— The rel was told in the London Gazette of January 11, 1780. by ! by Thomas Brown, Surgeon, near Glasgow, &c.-Art. 45. ART. VII. Philofophical Observations on the Senfes of Vision and Hearing; to which are added, a Treatise on Harmonic Sounds, and an Effay on Combuftion and Animal Heat. By J. Elliot, Apothecary. 8vo. 3.s. 6d. fewed. Murray. 1780. HIS collection of philofophical papers, and particularly those relating to Combuftion and Animal Heat, are the productions of a perfon evidently fmitten with the love of philofophy; and courting her, not unfuccefsfully; partly in the way of experiment, but principally (though, as it feems, not through choice) in the mode of theory and fpeculation. In the firft fection, which relates to Vifion, the Author defcribes the appearances that occurred in an experiment made with a view to afcertain the fenfations that would be excited in the Retina, without the action of light upon it; by means of a violent and long-continued mechanical preffure made with the hands on the eye-balls, in the direction of their axes. A concave hemifphere of light firft appears, chequered often in a very regular manner, with dark and lefs lucid intervals. Other appearances prefent themselves in fucceffion, ou increafing the preffure till the eyes become quite hot; at which time the lucid appearance nearly equals that which is experienced at noonday, when the eyes are open. The reader will be in pain for the hardy Experimenter, as he proceeds in reading the Author's account of the fucceeding fenfations, till the time when the luminous appearances totally vanished; fo as not to be renewed" on the continuance, or even in reafe, of the preffure. At this time the retina has loft all fenfation; fo that on removing the hands, and opening the eyes, the Author had the comfort to find himself totally blind; not being able to perceive the direct light of the fun itself. At length, however, but by degrees, the fenfibility of the organ is reftored. This experiment,' fays the Author, is very painful,' (and, we will add, not a little hazardous) and it is not every one that would choose to repeat it after me, with the requifite care.'-It is, we believe, a unique, and, we hope, will continue fo. For though, now that it has been made, we are much obliged to the Author for it; as fome of the appearances may throw new lights on certain difputed points relative to vifion; yet we would advife the curious reader to content himself with meditating only on the particulars that the Author has given of this fingular experiment. E 3 As As in this fection the Author defcribes luminous fenfations, which he had excited without the affiftance of light; fo in fome of the following fections he gives an account of what he calls internal founds, not excited by the vibrations of the external air, and which he had found means to produce, by preffing, dilating, or otherwise irritating the ear, at pleasure. These are not to be confounded with a mere ringing, or a rumbling and confused found in the ears: for the Author has, by practice and attention, and fometimes not without pain, as in the preceding cafe, been enabled to produce a regular though not complete fcale of diftinct founds; feveral of which he can excite with certainty, whenever he pleafes. It is very fingular too, that these founds do not vary, at different times, with respect to acuteness or gravity; as he has found, by comparing them occafionally with the notes of a fixed mufical inftrument, with which they happened to be in unifon; though he can make them lauder or weaker, by increafing or diminishing the irritation. For example, he fays that he could not, for a long time, excite a found in his left ear, lower than what was in unifon with the middle D of a German flute: but he has fince pro→ duced one as low as B. In his right ear he can now go two whole tones lower, or down to G. In my left ear,' he adds, I can raise notes from B to about an octave above, in all the intermediate gradations, or fenfible differences; but from thence, to a great part of another octave, I cannot yet excite them, though, ftill higher, they may be raised in great plenty, but in a more confused manner.' Were this scale of internal founds complete, and the commodious but selfish art of playing on a man's own ears-folus cum folo-eafily communicable, it would be pleafant enough to behold the gefticulations of the raw proficient in this art; who could not, like the fcraper on the violin, poffibly offend any one's ears but his own.To be more ferious: Thefe trials of the Author give occafion to many observations and speculations on the organ and fenfe of hearing, that have at least novelty to recommend them to the inquifitive reader; to whose perufal we likewise refer a fubfequent fection on the harmonical founds, or fons flutes, as the French call them; which are made on the violin, violoncello, trumpet marine, and other inftruments played on with a bow, and which are produced by means of a flight preffure of the finger upon the ftring. The principal part of this performance remains yet to be noticed; in which the Author propofes a new fyftem,-new at Jeaft at the time when this part of the work was compofed, and *ven when it was fent to the prefs-on the combuftion of bodies, the cause of animal heat, and other subjects connected with them. Under great difadvantages, and by dint of specus lation, without having time or opportunities either for making experiments himself, or acquiring a knowledge of many that had been made by others; the Author had formed a theory to account for thefe phenomena, which remarkably agrees with that which Mr. Crawford has lately propofed to the world; but chiefly deduced from experiments actually made by the latter. Of this laft theory, and of the experiments on which it is eftablifhed, we lately gave a particular account, in our Review for November laft, page 378. Of the conformity of this laft hypothesis with that of our prefent theorift the reader will judge, from the following fhort account of it; fo far as it tends to explain the theory of combuftion. When an inflammable body, alcohol for inftance, is fuffered to flame away; nothing but phlegm, an uninflammable substance, can be collected from it. The alcohol therefore has been intirely decomposed; and its phlogifton, in particular, has been feparated from it. Any quantity of air too, in which this procefs has been carried on till the flame has gone out, is found to be faturated with this principle, which the alcohol has loft, and which conftituted it an inflammable fubitance.-Now, as the flame, fays the Author, continued only while the air was, taking the phlogifton from the vapour, and went out when the air was no longer able to do this; it feems that the combuftion depended intirely on fuch action of the air on the phlogifton.' After obferving that the combination of certain fubftances with each other is attended with heat; Mr. Elliot fuppofes that the heat generated in the combuftion of bodies is occafioned by the phlogiston, contained in the inflammable body, combining with the air; or, to ufe his own words, that air has a greater affinity with phlogifton, than the fubftances have with which it is combined in inflammable bodies; and therefore when all circumstances properly concur, it attracts that principle from those bodies; that a fhining heat is generated by their combination; and that this decompofition, when once fufficiently begun in a perfectly inflammable body, together with the thining heat which is a consequence thereof, will be continued on the principles above laid down, without any farther affiitance from extraneous heat, as long as any of the fubftance remains.' Even in clofe veffels, where there is no communication with the external air, combuftion is nevertheless maintained, and that too with violence, if nitre be mixed with the combustible body because, fays the Author, it is now well known that nitre, or the nitrous acid, contains a quantity of common air, or rather indeed of air ftill more greedy of phlogiston, and therefore better, adapted to promote combuftion than common air. In the process of deflagration, the phlogifton, and this |