not this imperfection, and yet her own brother had the like
impediment with himself. This is somewhat singular ; unless
his father and mother were related to each other before mar-
riage, One of his sisters knows colours, the other does not ; the
last has two sons who have this imperfection, and a daughter
who is free from it. His own son and daughter know all co-
lours without exception.
Article 40. Description of a masl effectual Method of securing

Buildings againf Fire, invented by Charles Lord Viscount Ma-
hon, F.R.S.

As it is impoßible to abridge this interesting Article; and as the noble inventor has not in it explained the principles on which his method is founded; we shall confine ourselves to his account of two trials of it, made in the presence of the Prefident and some of the Fellows of the Royal Society, the LordMayor and Aldermen of London, several of the foreign ministers, and others.

The lower room of a building, which was about 26 feet long, by 10 wide, was filled with shavings and faggots, which were set on fire. — The heat was so intense, that the glass of the windows was melted, like so 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 side timbers, foorjoilts, or cieling-joists, damaged in the finallest degree; and the persons who went into the room immediately over the room filled with fire, did not perceive any ill effects from it whatever; even the Alpor of that room being perfe&tly cool during that enormous conflagration immediately underneath.'

To represent a timber-built town on fire, and to thew how effectually even a wooden building, secured in this manner, would stop the progress of the flames; a kind of timber building (of full so feet in length, and of three stories high in the middle) had been erected, quite close to one end of the secured wooden house. The former was filled and covered with above 1100 large kiln faggots, and several loads of dry shavings; and the whole pile was set on fire. The event is thus related :

· The height of the fame was no less than 87 feet perpen. dicular from the ground; and the grass upon a bank at 159 feet from the fire was all scorched : yet the fecured wooden building, quite contiguous to this valt heap of fire, was not ac ali damaged, except fume parts of the outer coat of plaster work.'-An attempt was next made to burn a wooden ftaire case, secured according to the inventer's method : but it refifted the flames, as if it had been constructed of fire-stone. Since this experiment, five other, still stronger, fires have been made on and under it; the whole space having been filled with

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shavings and large faggots : but this beftine stair-case is ftill standing, and is but little damaged.

The noble Inventor of this method proposes, in a short time, to give the world an account, in detail, of many other experiments on this important subject; and of the application of his method to different kinds of buildings, and to the different constituent parts of a house. He means likewise to add a full explanation of the principles upon which it is founded, and the reasons for its certain and surprising success. Article 5o. Track of his Majesty's armed Brig, Lyon, from

England 10 Davis's Streights, and Labrador, &c. By Lieutenant Richard Pickersgill, &c.

This Article is digested in a tabular form, and contains the daily obfervations made for determining the longitude by the sun and moon, the error of the common reckoning, the variation of the compass, dip of the needle, &c. as observed during the voyage in 1776. At the end of the paper, the Author, 'without meaning any personal reflection,' animadverts on the accounts given by others' of this part of the world, so little known, and so terribly represented.'— Having heard such dreadful stories of these countries,' he adds, I cannot help remarking it, as a circumstance equally fodlish and ridiculous; tending to mislead those who, from a laudable principle, would be benefactors to their country, but are decerred from it by such representations :'--and he declares his intention of publishing, in a short time, his observations on the ice, the atmosphere, the land of Forbilher, and the probability of a North-wesi paljuge *.

The remaining papers in this volume are-Article 28. Containing an Account of Baptilins, Marriages, and Burials, during 40 Years, in the Parish of Blandford Forum, Dorset; by Richard Pulteney, M. D. F.R. S.; where it appears that, on an average, there only dies i in 39 yearly.--Art. 30. Astrono.. mical Observations made in the Austrian Netherlands, in the Years 1773, 1774, and 1775; by Nathaniel Pigott, Erg; 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 Description of the Exocetus Volitans, or Flying Fij;

* I is to be feared that we fall have no more of thefe papers : M". P. Tarely lost his life by the oversetting of a boat on the Thames, as he was going on board a privateer, of which he had the scommand. The mencion of this accident, naturally fuggeits to us the melancholy idea of a ftill greater loss which the public hach sustained by the unfortunate death of, perhaps, the greatest navigator that ever e illed: Nred we add the celebrated name of Capt. Cook :Toe re was sold in the London Gazcue of January 11, 1780.

by by Thomas Brown, Surgeon, near Glasgow, &c.-Art. 45. Observations on the Solar Eclipse which happened June 24, 1778; by William Wales, F.R. S. &c.--and Art. 46. An Account of the fame Eclipse observed at Leicester ; by the Rev, Mr. Ludlam.

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Art. VII. Philofophical Observations on the Senses of Vision and Hear.

ing; to whi:h are added, a Treatise on Harmonic Sounds, and an
Elay on Combustion and Animal Heat. By J. Elliot, Apothecary.
8vo, 3.5. 6d. sewed. Murray. 1780.
HIS collection of philosophical papers, and particularly

those relating in Combustion and Animal Heat, are the productions of a person evidently smitten with the love of philofaphy; and courting her, not unsuccessfully; partly in the way of experiment, but principally (though, as it seems, not through choice) in the mode of theory and speculation.

In the first section, which relates to Vision, the Author describes the appearances that occurred in an experiment made with a view to ascertain the sensations that would be excited in the Retina, without the action of light upon it; by means of a violent and long-continued mechanical pressure made with the bands on the eye-balls, in the direction of their axcs. A concave hemisphere of light first appears, chequered often in a very regular manner, with dark and less lucid intervals. Other appearances present themselves in succession, ou increasing the pressure till the eyes become quite hot; at which time the lucid appearance nearly equals that which is experienced at noon day, when the eyes are open. The reader will be io pain for the hardy Experimenter, as he proceeds in reading the Author's account of the succeeding sensations, till the time when the Juminous appearances totally vanished; so as not to be renewed on the continuance, or even in rease, of the pressure. At this time the retina has lost all sentation; so 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 sun itself

. At length, however, but by degrees, the fenfibility of the organ is restored.

• This experiment,' says 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 requisite 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 some of the appearances may throw new lights on certain disputed points relative to vifion; yet we would advise the curious reader to content himself with meditating only on the particulars that the Author has given of this fingular experiment,

As in this section the Author describes luminous sensations, which he had excited without the allistance of light; so in some of the following sections 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 prefling, dilating, or otherwise irritating the ear, at pleasure. These are not to be confounded with a mere ringing, or a rumbling and confused sound in the ears: for the Author has, by practice and attention, and sometimes not without pain, as in the preceding case, been enabled to produce a regular though not complete scale of distinct sounds; feveral of which he can excite with cero tainty, whenever he pleases. It is very singular too, that there founds do not vary, at different times, with respect to acriteness or gravity; as he has found, by comparing them cccasionally with the notes of a fixed musical instrument, with which they happened to be in unison ; though he can make them louder or weaker, by increafing or diminishing the irritation.

For example, he says that he could not, for a long time, excite a found in his left' ear, lower than what was in unison with the middle D of a German Aute: but he has since 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 interinediate gradations, or fenfible differences ; but from thence, to a great part of another octave, I cannot yet excite them; though, fill higher, they may be raised in great plenty, but in a more confused manner.'

Were this scale of internal sounds complete, and the commodious but selfish art of playing on a man's own ears - folus cum folo-easily communicable, it would be pleasant enough to be"hold the gesticulations of the raw proficient in this art; who could not, like the scraper on the violin, possibly offend any one's ears but his own.To be more serious:--Thefe trials of the Author give occafion to many observations and Speculations on the organ and sense of hearing, that have at least novelty to recommend them to the inquisitive reader ; to whose perural we likewise refer a subsequent section on the harmonical founds, or fons flutés, as the French call them ; which are made on the violin, violoncello, trumpet marine, and other instruments played on with a bow, and which are produced by means of a Aight pressure of the finger upon the string,

The principal part of this performance remains yet to be noticed; in which the Author proposes a new fyftem,-new at Jeast at the time when this part of the work was composed, and Even when it was sent to the press on the combustion of bodies, the cause of animal heat, and other subjects connected with them. Under great disadvantages, and by dint of specu


lation, without having time or opportunities cither 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 these phenomena, which remarkably agrees with that which Mr. Crawford has lately proposed to the world; but chiefly deduced from experiments actually made by the latter. Of this last theory, and of the experiments on which it is established, we lately gave a particular account, in our Review for November last, page 378. Of the conformity of this last hypothefis with that of our present theorist the reader will judge, from the following short account of it; so far as it tends to explain the theory of combustion.

When an inflammable body, alcohol for infance, is suffered to fame away: nothing but phlegin, an uninflammable substance, can be collected from it. The alcohol Therefore has been intirely decomposed; and its phlogiston, in particular, has been separated from it. Any quantity of air too, in which this process 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 constituted is an infiammable substance. Now, as the Aame, lays the Author, ' continued only, while the air was, taking the phlogiston from the vapour, and went out when the air was no longer able to do this; it seems that the combustion depended intirely on such action of the air on the phlogiston.'

After observing that the combination of certain substances with each other is attended with heat; Mr. Elliot supposes that the heat generated in the combustion of bodies is occafioned by the phlogiston, contained in the infiammable body, combining with the air; or, to use his own words, that air has a greater affinity with phlogiston, than the fubitances 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 shining heat is generated by their combination, and that this decompofition, when once fufficiently begun in a perfectly inflammable body, together with the shining heat which is a consequence thereof, will be continued on the principles above laid down, without any farther affiltance from extraneous heat, as long as any of the subftance remains.'

Even in close vessels, where there is no communication with the external air, combustion is nevertheless maintained, and that too with violence, if nitre be mixed with the combustible body: because, says 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 combustion than common air, lo the process of defagration, the phlogiston, and this

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