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

It is pretty fingular, that while charcoal yields inflammable air, the air from foot is pure or dephlogifticated, till the foot is burnt to the ftate of charcoal, and then it produces the fame kind of air as other charcoal. Fresh burnt charcoal exposed to the atmosphere, imbibes air, and emits it again on being immerfed in water: this is found to be no other than common air, fo that the phlogiftication of the air expelled from it by heat muft proceed from a decompofition of the charcoal.

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

The colour of fpirit of nitre is known to be owing to phlogifton, and the Doctor has found that this phlogifton is, in certain circumstances, communicated to it by light. The dephlogifticated and colourlefs acid, expofed to light in a vial quite full, received no colour; but when there was a confiderable vacancy above the liquor, the vapours rifing into this fpace foon received a tinge from light, and gradually communicated it to the fubftance 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 faw-duft, then filling it up with plumbum corneum, covering it close with its lid, and fetting its bottom on burning coals, that the faw-duft may be charred, without melting the lead, an operation of very great nicety: when the vapour ceases to iffue at the joining of the lid, it is fecured, while hot, with fealing wax, to exclude external air. On opening it when cold, the lead, now black, exhibits ignited fparks, which spread more and more, the metal at the fame time reviving into minute globules.

2. A letter from Mr. Henry of Manchefter, 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 fubftance; that cauftic 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 cauftic again by merely feparating the phlogifton. We fhewed the fallacy of the experiments which he adduced in fupport of this theory; and Mr. Henry's experiment goes to a direct proof, that cauftic alcalies are not made mild by inflammable air, which, if it is not one of the purest forms of phlogifton, certainly contains more of that principle than is contained in fixed air. Ch

ART. VII. Tranfactions of the American Philofopbical Society, held at Philadelphia, for the promoting ufeful Knowledge. Vol. II. 4to. 18s. Boards. Philadelphia printed, and fold by Dilly in London, 1786.

HE firft volume of thefe American tranfactions was pub

we gave a particular account of the origin and eftablishment of this fociety. The peculiar circumftances of America, during the late troubles, are a fufficient apology for the delay of thefe western philofophers in publishing a continuation of their inquiries and difcoveries; but peace and tranquillity being at length reftored, they have refumed their fcientific labours, and have prefented the Public with this fecond volume of their tranfactions.

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

In the year 1780, the fociety was incorporated, by a charter paffed in the affembly of the freemen of the commonwealth of Pennsylvania. The charter contains nothing but what is usual in fimilar cafes; the claufes are cautiously worded, and well adapted to the purpose of incorporating a learned body.

Mr. J. H. Magellan of London, offered to the fociety a prefent of two hundred guineas, the intereft of which to be difpofed of, in annual premiums, to the authors of the beft difcoveries, or moft useful improvements relating to navigation, natural philofophy, &c. This generous offer was thankfully accepted. After the conditions and rules for the difpofal of thefe premiums, we have a lift of the officers and members of this fociety, among whom we recognize the names of feveral refpectable and learned European philofophers.

The papers which compofe this volume are mifcellaneous, and follow each other without any regard to fubject or connection; in our account of them we fhall, however, purfue our usual method of arrangement, under feparate heads, beginning with fuch papers as belong to

*Review, vol. xlvii. p. 333.

NATURAL

NATURAL HISTORY and PHILOSOPHY.

Defcription of the white Mountains in New Hampshire. By the Rev. Jeremy Belknap.

Thefe white mountains are the higheft lands in New England. They are difcovered by veffels coming on the eaftern coaft before all other land; on the fhore they are vifible for 80 miles on the fouth and fouth-aft fides, and are faid to be plainly feen from the neighbourhood of Quebec. They extend in a direction north-east and fouth-weft. The fides of the mountains are covered with fpruce trees; the furface is compofed of loofe rocks covered with long green mofs.

The rocks,' fays our Author, of which thefe mountains are compofed, are in fome paris flint, in others flate; but toward the top, a dark grey ftone, which, when broken, fhows fpecks of ifingglafs. On the bald parts of the mountains the tones are covered. with a fhort grey mofs, and at the very fummit the moss is of a yel- ̧ lowish colour, and adheres firmly to the rock.

Eight of our company afcended the highest mountain on the 24th of July, and were fix hours and fifty-one minutes in gaining the fummit. The fpruce-firs, as you afcend, grow fhorter till they degenerate to fhrubs and bushes, then you meet with low vines bearing a red and a blue berry, and laftly a fort of grass mixed with

mofs.

6

Having afcended the steepest precipice you come to what is called the plain, where the afcent becomes gentle and eafy. This plain is compofed of rocks covered with winter grafs and mofs, and looks like the furface of a dry pasture or common. In fome openings between the rocks you meet with water, in others dry gravel. The plain is an irregular figure, its area uncertain, but from its eaftern edge to the foot of the fugar-loaf is upwards of a mile; on the western fide it extends farther. The fugar-loaf is a pyramidal heap of loose grey rocks, not lefs than 300 feet in perpendicular height, but the afcent is not fo difficult as the precipice below the plain. From this fummit in clear weather is a noble view, extending to the ocean on the fouth-east, to the highlands on the weft and north-weft, which feparate the waters of Connecticut River from thofe of Lake Champlain and St. Lawrence; on the fouth it extends to Winipileogee Lake, and the highlands fouthward of Pemigewaffet river.

It happened unfortunately for our company that a thick cloud covered the mountain almost the whole time that they were on it, fo that fome of the inftruments 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 inftruments at the foot of the mountain, at the fame time that others were carried to the top; but they were unhappily broken in the courfe of our journey; and the barometer which was carried to the fummit had fuffered fo much agitation, that an allowance was neceffary to be made in calculating the height of the mountain, which our ingenious companion, the Rev. Mr. Cutler of Ipswich, eftimates in round numbers

at

at 5500 feet above the meadow, the meadow being 3500 feet above the level of the fea; and this feems to be as low an eftimation as can be admitted. We intended to have made a geometrical menfuration of the altitude; but in one place where we attempted it we could not obtain a base of a fufficient length, and in another where this convenience (we fuppofe our Author means inconvenience) was removed, we were prevented by the almost continual obfcurations of the mountains by the clouds.

-Thefe immenfe heights which I have been defcribing, being copiously replenished with water, exhibit a variety of beautiful caf cades, fome of which fall in a perpendicular fheet or fpout, others are winding and narrow, others fpread on the level furface of fome wide rock, and then gufh in cataracts over its edges. A romantic imagination may find full gratification amidst thefe rugged fcenes, 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. Amonoofuck and Ifrael rivers, two principal branches of Connecticut, fall from the western fide of the mountains, Peabody river, and another branch of Amarifcogin from the north-eastern fide, and almost the whole of Saco defcends from the fouthern fide. The declivities being very steep cause this latter river to rife very fuddenly in a time of rain, and as fuddenly to fubfide.

-We found no ftones of higher quality than flint; no limeftone, though we tried the most likely with aquafortis. It is faid there is a part of the mountain where the magnetic needle refufes to traverse; this may contain rock ore, but our guide could not find the place. It is alfo faid that a mineral, fuppofed to be lead ore, has been discovered on the eastern fide. One of the fprings which we met with in our afcent on that fide afforded a thick frothy fcum and a faponaceous tale. All fearches for fubterraneous treafures in thefe mountains have as yet proved fruitless. The most certain riches which they yield are the frefhets [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 most luxuriant plenty.'

Thele mountains feem to afford ample matter for the obfervation and examination of future philofophers; they may contain a vaft fund of wealth, and be the fource of immenfe riches to the country; and we doubt not that the fhort account here given by Mr. B. will ferve to excite, in fome inquifitive perfons, a defire of minutely examining them with a view to afcertain 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 Mefirs. Hare and Skinner, filk merchants in London, procured for Dr. M. from one of the firft houfes in Italy, contains the Italian method of managing the filk worms, and obtaining the raw filk. After the interefting and curious method of managing filk worms in England, by Mifs Rhodes, which we gave in our Review for December laft, page 422, we apprehend the prefent account, though important

in

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

I examined the eye with all the attention in my power, being no way difpofed to credit common report, but rather expecting to detect a fraud or vulgar prejudice: I was much furprised, however, to fee a real living worm within the ball of the horfe's eye. This worm was of a clear white colour, in fize and appearance much like a piece of fine bobbin; it feemed to be from 2 to 3 inches in length, which, however, could not be duly afcertained, its whole length never appearing at one time, but only fuch a portion as could be feen through the iris, which was greatly dilated. The worm was in a conftant, lively, vermicular motion; fometimes retiring fo deep into the eye as to become totally invifible, and at other times approaching fo near to the iris as to be plainly and diftinctly feen; at leaft fo much of it as was within the field of the iris.'

How this animal was conveyed into the cavity of a found eye is not perhaps eafy to determine. We could have wifhed to have seen a more accurate defcription of the worm in question. The horse, who lived in mifery, fhould have been killed, and the eye fhould have been diffected.

Of a living Snake in a living Horfe's Eye. By John Morgan, M. D. F. R. S.

This account coincides with that of the fame cafe given in the preceding article. Dr. Morgan hopes to be able to give a more circumftantial detail of this extraordinary phenomenon, from a diffection of the eye.

An Account of an electrical Eel, or the Torpedo of Surinam. By William Bryant, Efq.

The first duty of a naturalift is to defcribe his object, and then proceed to recount its feveral qualities. Mr. Bryant, though he has been deficient in his defcription of the animal in quef tion, has amply recorded the electrical phenomena it affords, which appear nearly fimilar to thofe obfervable in the gymnotus elec tricus, frequently mentioned in our Journal. This fish, however, feems to have very ftrong electrical powers, as appears by the following paffage :

I am fometimes 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 ferves him as a weapon of defence against his enemies. For I have often obferved, that, on firft taking hold of him, the fhock is tolerable; but as foon as he perceives himself the leaft confined, it is much more violent. This I experienced to my coft, as I one day took hold of him about the middle and lifted him partly out of the water, when on a fudden I received fo fmart a fhock 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, confult our General Index.