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consumed; which on being put on a piece of ignited charcoal, is reduced, at least in part, to a metallic state. The Author considering the great quantity of sulphur contained in the Derbyshire lead ores, where about 10,000 tuns are smelted annually, proposes to the consideration of the lead smelters the practicability of collecting it; both as a lucrative business to themselves, and a great saving to this country, where, it seems, we at prefent import the sulphur we use. For this purpose, he suggests the poffibility of collecting it, in long, large, and winding horizontal chimneys, connected with the furnaces in which the ore is roasted : in the same manner as is practised in Saxony, where arienic is procured by a similar contrivance; the arseni. cal vapour being condensed, and attaching itself, like foot, to the sides of the chimney; from which the arsenic is, from time to time, swept out.

At the end of this paper, the Author relates fome experiments from which it appears that, though the surface of pure melted lead becomes covered with a pellicle of various colours; yet these appearances do not occur if a small portion of tin be mixed with the lead, even when the weight of the tin scarce exceeds the zooth part of the weight of the lead, Zinc possesses the same property, in this particular respect, as tin. After the tin has been reduced to a calx, by the continuance of the heat, the lead again acquires its property of forming colours; which successively appear in the following order : yellow, purple, blue, yellow, purple, green, pink, green, pink, green. The rationale of these appearances may be deduced from the well-known experiments and theory of Sir Isaac Newton, lately illustrated and confirmed by Mr. Delaval, in his ingenious Experimental Enquiry respecting the changes of colours in bodies MISCE 4.7 ANEOUS

ARTICLES. Article 26. An Account of the Island of St. Miguel. By Mr.

Francis Masson, This island is one of the principal of the Azores. The only particulars relating to it, that can entitle this account of it to a place in the Philosophical Transactions, are contained in a general description of some fountains, from which the water

up so hot, that a person cannot dip his finger into it without being scalded.' A steam likewise rises, to a considerable height, from several apertures, which is so hot, that no one can approach it with the hand. In other places, says the Author, "a person would think that a hundred smiths bellows were blowing altogether, and sulphureous steams issuing out [issue out] in thousands of places, so that native sulphur is found in

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every chink, and the ground covered with it like hoar frost; even the bushes that happen to lie near these places are covered with pure brimstone, condenling from the steam that iffues our of the ground, which in many places is covered over with a substance like burnt alum.' Though the Author appears to have been in poffeffion of a thermometer; no account is given of the attual temperature of these waters.

Near these boiling fountains, there are several cold mineral springs; two of which are said to send forth waters - which have a very strong mineral quality, of an acid taste, and bitter to the tongue.' - Seven specimens of these and other waters have been lent home, and aré enumerated at the end of this Article. The first of these was taken from one of these cold fountains; which is described as giving a strong acid water.'-As this Arong acid water appears to us a very great curiosity, we could have wished that its analysis had been Tubjoined to this Atticle; as well as, indeed, that of the hot waters above mentioned, which are said to posless considerable virtues in the cure of the dead pally, eruptions, and more particularly the gout. While the Author refided near these waters, several old gentlemen, who were quite worn out with the said disorder, were ofing the waters, and had received incredible benefit from them. He accordingly hints, that should any person venture so far for his health, a small stock of the superfluities of life only need to be laid in, as the illand yields every necessary, and the climate is very temperate. Article 27. An Account of a remarkable Imperfeétion of Sight. In

a Letter from Mr. J. Scott, &c. The person who here communicates several extraordinary particulars of an hereditary infirmity in the visual organs, with respect to colours, can fee obje&s at a distance, and distinguish their form and bulk as well as most men: but such is his fina gular idiosincrasy with respect to their colour, that he declares,

though his bufiness was behind a counter many years, where he had to do with a variety of colours'' he does not know ang green in the world ; a pink colour, and a pale blue ate alike. He has often thought a full red and a full green the ļame, or a good match : though he can discern the difference between yellow and a full blue. He relates an anecdote of his having been offended at an intended fon-in-law's having entered his house, on the day preceding his marriage, in a new fuit of cloaths, which appeared as much a black to his eyes, as any black that ever was dyed; while the gentleman had actually decorated himself with a fine rich claret-coloured dress.

We have called this imperfection hereditary; but, like ferdigitism, it appears to have affected owly fome individuals of his fainily. He derived it from his father, but his mother bad

not this imperfection, and yet her own brother had the like impediment with himself. This is somewhat fingular ; unless his father and mother were related to each other before marriage. One of his lifters knows colours, the other does not; the laft has two sons who have this imperfection, and a daughter who is free from it. His own son and daughter know all colours without exception. Article 40. Defcription of a mali effettual Method of securing

Buildings against Fire, invented by Charles Lord Viscount Mahon, 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 Thall confine ourselves to his account of two trials of it, made in the presence of the President 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 16 widt, 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 sun down in drops ; yet the flooring boards of that very room were not burnt through, nor was one of the side timbers, foorjoists, or cieling-joists, damaged in the smallest 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 floor of that room being perfectly 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 progrefs 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 perpendicular from the ground; and the grass upon a bank at 150 feet from the fire was all scorched: yet the secured wooden building, quite contiguous to this vaft heap of fire, was not at all damaged, except some parts of the outer coat of plaster work.'.-An atteni pe was next made to burn a wooden ftaire cafe, secured according to the inventer's method: but it refifted the flames, as if it had been constructed of fire-ftone. Since this experiment, five other, Itill frooger, fires have been made og and under it; the whole space having been filled with

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shavings and large faggots : 'but this Asbeftine stair-case is fill ftanding, and is but little damaged.

The noble Inventor of this method proposes, in a fhort 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 fuccess. Article 50. Track of his Majesty's armed Brig, Lyon, from

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

This Article is digested in a tabular form, and contains the daily observations 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 oblerved during the voyage in 1776. At the end of the paper, the Author,' with out meaning any personal reflection,' animadverts on the ac. counts given by other's “ 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 foolith and ridiculous; tending to mislead those who, from a laudable principle, would be benefactors to their country, but are deterred from it' by-fuch representations :'-and he declares his intention of publishing, in a short time, his observations on the ice, the atmosphere, the land of Forbilber, and the probability of a North-west palage *.

The remaining papers in this volume are--Article 28. Conraining an Account of Baptisms, 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, Efq; F.R.S. &c.-- Art. 34: An Account of the Blue Sbark, together with a Drawing of the fame; by W. Watson, jun. M. D. F.R.S.Art. 35+ A Defcription of the Exocoetus Volitans, or Flying Fift;

It is to be feared tha: we shall have no more of these papers : Mr.P. la:ely lost his life by the oversecting 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 fuggelts to as the melancholy idea of a still greater loss which the public hath sustained by the unfortunate death of, perhaps, the greatest navigator that ever exilied: Need we add the celebrated name of Cape. Cook ? The relt was told in the London Gazette of January 11, 1780.

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

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ART. VII. Philosophical Observations on the Senses of Vifion and Hear.

ing;' 10 whi:h are added, a Treatise on Harmonic Sounds, and an Ejay on Combuflion and Animal Heat. By J. Elliot, Apothecary. 8vo. 3 s. 6d. rewed. Murray. 1780. HIS collection of philosophical papers, and particularly

those relating to Combustion and Animal Heat, are the productions of a person evidently smitten with the love of philoTophy; 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 defcribes 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 hands on the eye-balls, in the direction of their axes. 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 fucceffion, on increasing the pressure 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 succeeding senlations, till the time when the luminous appearances totally vanished; so as not to be renewed on the continuance, or even in reale, of the pressure. At this time the retina has lost all sensation; 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 sensibility 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 so. 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 vision; yet we would advise the curious reader to content himself with medicating only on the particulars that the Author has given of this fingular experiment,

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