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this ground, fluor would appear to be volcanic, for it yielded the least air of all the bodies examined, less even than glass.

It is pretty fingular, that while charcoal yields infiammable air, the air from foot is pure or dephlogisticated, till the foot is burnt to the state of charcoal, and then it produces the same kind of air as other charcoal. Fresh burnt charcoal exposed to the atmosphere, imbibes air, and emits it again on being immersed in water : this is found to be no other than common air, so that the phlogistication of the air expelled from it by heat must proceed from a decomposition of the charcoal.

The permeability of bladders to different kinds of air is fully ascertained, part of the included air having paffed out, and the exterior air having pafled in, through the fubitance of the bladder. Inflammable air and dephlogisticated air, which when fimply mixed together, appear to have no action upon one another, by this slow mode of mixture through a bladder (that is, by keeping a bladder of inflammatle air in a jar of dephlogisticated air) unite together and form fixed air.

The colour of spirit of nitre is known to be owing to phlogiston, and the Doctor has found that this phlogiston is, in certain circumstances, communicated to it by light. The dephlogisticated and colourless acid, exposed to light in a vial quite full, received no colour, but when there was a considerable vacancy above the liquor, the vapours rifing into this space foon received a tinge from light, and gradually communicated it to the substance of the liquor.

An Appendix to this volume contains:

1. A letter from Mr. Keir, on a new kind of metallic pyrophorus; which is prepared, by filling a cylindrical box of its height with saw.dult, then filling it up with plumbum corneum, covering it close with its lid, and setting its bottom on burning coals, that the faw-dult inay be charred, without melting the lead, an operation of very great nicety: when the vapour ceases to issue at the joining of the lid, it is secured, while hot, with sealing wax, to exclude external air. On opening it when cold, the lead, now black, exhibits ignited sparks, which spread more and more, the metal at the same time reviving into minute globules.

2. A letter from Mr. Henry of Manchester, giving an account of an experiment which confirms one of our remarks upon Mr. Delaval's paper on colours in the Manchester Memoirs * Mr. Delaval contends, that fixed air acts, not as an acid, but merely as a phlogiflic substance; that caustic alcalies become mild by uniting fimple phlogifton with them, equally as by fixed

• See Monthly Review for May 1786, p. 359.

air; and that they become caustic again by merely separating the phlogiston. We shewed the fallacy of the experiments which he adduced in support of this theory, and Mr. Henry's experiment goes to a direct proof, that caustic alcalies are not made mild by inflammable air, which, if it is not one of the purest forms of phlogiston, certainly contains more of that principle than is contained in fixed air.

Ch

ART. VII, Transactions of the American Philofopbical Society, held at

Philadelphia, for the promoting useful Knowlerge. Vol. II. 4to. 185. Boards. Philadelphia printed, and sold by Dilly in London,

1786.

THE

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HE first volume of these American transactions was pub

lished in the year 1772. In we gave a particular account of the origin and establishment of this society. The peculiar circumstances of America, during the late troubles, are a sufficient apology for the delay of these weitern philosophers in publishing a continuation of their inquiries and discoveries; but peace and tranquillity being at length restored, they have resumed their scientific labours, and have presented the Public with this second volume of their transa&tions.

Prefixed to this volume we have an account of the laws and regulations of the society, which is, in substance, the fame with that already laid before our readers, in our former account.

In the year 1780, the society was incorporated, by a charter passed in the assembly of the freemen of the commonwealth of Pennsylvania. The charter contains nothing but what is usual in fimilar cases; the clauses are cautiously worded, and well adapted to the purpose of incorporating a learned body.

Mr. J. H. Magellan of London, offered to the society a prefent of two hundred guineas, the interest of which to be disposed of, in annual premiums, to the authors of the best discoveries, or most useful improvements relating to navigation, natural philosophy, &c. This generous offer was thankfully accepted. After the conditions and rules for the disposal of these premiums, we have a list of the officers and members of this society, among whom we recognize the names of several respectable and learned European philosophers.

The papers which compose this volume are miscellaneous, and follow each other without any regard to subject or connection; in our account of them we shall, however, pursue our usual method of arrangement, under separate heads, beginning with such papers as belong to

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* Review, vol. xlvii. p. 333.

NATURAL

NATURAL HISTORY and PHILOSOPHY. Description of the white Mountains in New Hampshire. By the

Rev. Jeremy Belknap. These white mountains are the highest lands in New England. They are discovered by veffels coming on the eastern coail before all other land; on the shore they are visible for 80 miles on the south and south-east sides, and are said to be plainly seen from the neighbourhood of Quebec. They extend in a direction north-eait and south-west. The fides of the mountains are covered with spruce trees ; the surface is composed of loose rocks covered with long green moss.

The rocks,' says our Au:hor, of which these mountains are composed, are in some paris flint, in others slate ; but toward the top, a dark grey itone, which, when broken, shows fpecks of ingglass. On the bald parts of the mountains the stones are covered. with a short grey moss, and at the very summit the muls is of a yel-, lowish colour, and adheres firmly to the rock.

• Eight of our company ascended the highest mountain on the 24th of July, and were fix hours and fifty-one minutes in gaining the fummit. The spruce-firs,

The spruce-firs, as you ascend, grow shorter till they degenerate to Mrubs and bushes, then you meet with low vines bearing a red and a blue berry, and lastly a fort of grass mixed with moss.

Having ascended the steepest precipice you come to what is call. ed the plair, where the ascent becomes gentle and easy. This plain is composed of rocks covered with winter grass and moss, and looks like the surface of a dry pasture or common. In some openings between the rocks you meet with water, in others dry gravel. The plain is an irregular figure, its area uncertain, but from its eastern edge to the foot of the lugar-loaf is upwards of a mile; on the western side it extends farther. The sugar-loaf is a pyramidal heap of loose grey rocks, not less than 300 feet in perpendicular height, but the ascent is not so difficult as the precipice below the plain. From this summit in clear weather is a noble view, extending to the ocean on the south-east, to the highlands on the west and north-west, which separate the waters of Connecticut River from those of Lake Champlain and St. Lawrence; on the south is extends to Winipileogee Lake, and the highlands'southward of Pemigewasset river.

• It happened unfortunately for our company that a thick cloud covered the mountain almost the whole time that they were on it, so that some of the instruments which with much labour they had carried up, were useless. In the barometer the mercury ranged at 22:6 inches, in 44 degrees of heat by Fahrenheit's thermometer. It was our intention to have placed one of each of these initruments at the foot of the mountain, at the same time that others were carried to the top; but they were unhappily broken in the course of our journey; and the barometer which was carried to the summit had suffered so much agitation, that an allowance was necessary to be made in calculating the height of the mountain, which our ingenious companion, the Rev. Mr. Cutler of Ipswich, estimates in round numbers at 5500 feet above the meadow, the meadow being 3500 feet above the level of the sea; and this seems to be as low an estimation as can be admitted. We intended to have made a geometrical mensuration of the altitude; but in one place where we attempted it we could not obtain a base of a sufficient length, and in another where this convenience (we suppose our Author means inconvenience) was removed, we were prevented by the almost continual obscurations of the mountains by the clouds.

' -These immense heights which I have been describing, being copiously replenished with water, exhibit a variety of beautiful calcades, some of which fall in a perpendicular sheet or spout, others are winding and narrow, others spread on the level surface of some wide rock, and then guth in cataracts over its edges. A romantic imagination may find full gratification amidst these rugged scenes, if the ardour be not checked by the fatigue of the approach. Three of the largest rivers in New England receive the greatest part of their waters from this region. Amonoosuck and Israel rivers, two principal branches of Connecticut, fall from the western side of the mountains, Peabody river, and another branch of Amariscogin from the north-eastern side, and almost the whole of Saco descends from the southern fide. The declivities being very steep cause this latter river to rise very suddenly in a time of rain, and as suddenly to subside.

'~We found no ftones of higher quality than flint; no limeftone, though we tried the most likely with aquafortis. It is said there is a part of the mountain where the magnetic needle refuses to traverse; this may contain rock ore, but our guide could not find the place. It is also said that a mineral, supposed to be lead ore, has been discovered on the eastern side. One of the springs which we met with in our ascent on that fide afforded a thick frothy scum and a saponaceous talle. All searches for subterraneous treasures in these mountains have as yet proved fruitless. The most certain riches which they yield are the freshets (we are unacquainted with this word), which bring down the foil to the intervals below, and form a fine mould, producing corn, grain, and herbage, in the molt luxuriant plenty.'

There mountains seem to afford ample matter for the observation and examination of future philosophers; they may contain a vast fund of wealth, and be the source of immense riches to the country; and we doubt not that the short account here given by Mr. B. will serve to excite, in some inquisitive persons, a defire of minutely examining them with a view to ascertain their productions, both external and internal. The whole Progress of the Silk Worm, from the Egg to the Cocon.

By Dr. John Morgan. This account, which Meffrs. Hare and Skinner, filk merchants in London, procured for Dr. M. from one of the first houses in Italy, contains the Italian method of managing the filk worms, and obtaining the raw filk. After the interesting and curious method of managing silk worms in England, by Miss Rhodes, which we gave in our Review for December last, Page 422, we apprehend the present account, though important

in

in Italy, and other places of nearly the same climate, will not afford, to an English reader, much entertainment or information, Account of a Worm in a Horse's Eye. By F. Hopkinson, Esq. This very extraordinary care is thus related :

• I examined the eye with all the attention in my power, being no way disposed to credit common report, but rather expecting to detect a fraud or vulgar prejudice: I was much surprised, however, to see a real living worm within the ball of the horfe's eye.

This worm was of a clear white colour, in size and appearance much like a piece of fine bobbin ; it seemed to be from 24 to 3 inches in length, which, however, could not be duly ascertained, its whole length never appearing at one time, but only such a portion as could be seen through the iris, which was greatly dilated. The worm was in a constant, lively, vermicular motion ; sometimes retiring so deep into the eye as to become cotally invisible, and at other times approaching so near to the iris as to be plainly and distinctly feen; at least so much of it as was within the field of the iris.'

How this animal was conveyed into the cavity of a sound eye is not perhaps easy to determine. We could have wilhed to have seen a more accurate description of the worm in question. The borse, who lived in misery, thould have been killed, and the eye

should have been dificcted. Of a living Snake in a living Horse's Eye. By John Morgan,

M. D. F. R. S. This account coincides with that of the same case given in the preceding article, Dr Morgan hopes to be able to give a more circumstantial detail of this extraordinary phenomenon, from a diffe&tion of the eye. An Account of an electrical Eel, or the Torpedo of Surinam. By

William Bryant, Esq. The first duty of a naturalist is to describe his object, and then proceed to recount its several qualities. Mr. Bryant, though he has been deficient in his description of the animal in ques. tion, has amply recorded the electrical phenomena it affords, which appear nearly fimilar to those observable in the gymnotus elec. tricus, frequently * mentioned in our Journal. This filh, however, feems to have very strong electrical powers, as appears by the following passage :

• I am sometimes apt to conjecture that this animal has the power of communicating the stroke when, and with what degree of force it will; and that it serves him as a weapon of defence against his enemies. For I have often observed, that, on first taking hold of him, the shock is tolerable; but as soon as he perceives himself the least confined, it is much more violent. This I experienced to my cost, as I one day took hold of him about the middle and lifted him partly out of the water, when on a sudden I received so smart a shock that

* See particularly Rev. vol. li. p. 219. lii: p. 332 and 577. liv. p. 22. lv. p. 410. and in other places, for which, consult our General Index.

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