In the fecond experiment with the pieces of cloth and filk, and in the 3d, with only the boiled water, no air could be expected, as that water had, in the boiling, been deprived of all the air it originally contained-and as to the 4th experiment, the refult is obvious, the addition of the common air in the unboiled water, adding to the quantity, but tainting the quality of the dephlogisticated air yielded by the vegetable.

Our Author proceeds now to apply thefe, and fome other facts and inferences, to the queftion in agitation between him and Dr. Priestley. It has always been obferved that the airbubbles yielded by vegetables, iffue from, or feem to adhere to, only one fide of the leaves, generally the under-fide.-Now the Doctor contends, that if it were the water, and not the plant that yields the air, this diftinction would not take place, as no reafon could be affigned for fuch a predilection. Moreover, according to Dr. P.'s hypothefis, the quantity of air yielded in thefe proceffes, fhould be proportionate to the quantity of water in which it is produced; and the water fhould, after the process, be deprived of air: but this our Author never found to be the cafe, the quantity of air being always proportionate to the quantity of vegetable contained in the water; and the water nor only fparkling confiderably, like all fluids in which air is contained, but even yielding much air by heat.

If it were merely the contact with the vegetable that purified the air, as Dr. Prieftley maintains, it fhould feem, fays our Author, that the purity would be proportionate to the length of the contact; but that this is not the cafe the inftances of feveral American and fleshy plants are adduced, which yield air of the beft quality, in fuch quantity that the bubbles fcarce remain an inftant in contact with the leaves.

It should also follow from Dr. P.'s theory, that plants closed up from the common atmosphere would not of themselves yield any air. Our Author relates an experiment he made to prove the contrary of that inference: a plant inclosed in a glass tube from which the outward air was excluded, having, without the medium of water, not only increased the quantity of air within. the tube, but alfo greatly improved its quality. The copious ftreams of air yielded by the Agave Americana, are, lafily, mentioned, as a ftriking inftance, which our Author thinks fhould fatisfy the moft incredulous concerning the truth of his theory, that the air proceeds from the vegetable, and not from the water.He concludes his paper with fome hints concerning the ufe that might be made of this property of plants for the preservation of animal life. Among other things, it is fuggefted, that fprinkling the water in which air has been produced from vegetables, on the floor, and even frequently ftirring it, may prove very beneficial for purifying the air tainted by frequent refpiration, or by other phlogifticating caufes. REV. Nov. 1783.

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Art. 22.

ELECTRICITY.

Proceedings relating to the Accident by Lightning at
Heckingham.

This article is introduced by a letter from the Board of Ordnance to the Prefident of the Royal Society, acquainting him that a ftroke of lightning had fet fire to the poor-house at Heckingham, notwithstanding it was armed with eight pointed conductors; and requesting to know what authentic intelligence had been received on that fubject. The Prefident and Council appointed a Committee to examine into the accident; and it is the report of this Committee, which confifted of Dr. Blagden and Mr. Nairne, that forms the main part of this paper.

On the 17th of June 1781, about three in the afternoon, after a form of fome duration, a violent clap of thunder was heard, foon after which the fouth-eaft corner of the building was obferved to be on fire: this was immediately extinguished, and it was found that the lightning had made a crack in the wall, down that corner of the building, broke and displaced three courfes of pantiles on the roof of a ftable adjacent to the houfe, damaged a faddle that hung on a nail in the ftable, and by that interrupted communication defcended into the ground.

The point of the nearest conductor was 69 feet from the place ftricken. This, as well as all the conductors, communicated in their whole extent with nothing better to carry off electricity than mafonry and timber, and terminated in contact with the brick work at the bottom of floping drains. This mode of erecting conductors will no doubt appear reprehenfible to those who are verfed in electricity; but in this inftance it must be obferved, that the accident happened in the midft of a heavy ftorm of rain and hail, which had lafted for near 20 minutes before the clap: and that confequently the whole building was wet, and the drains neceffarily full of water. Art. 24. Account of a new Electrometer. By Mr. Abraham

Brook.

The principle of this inftrument is, like that of all other electrometers, founded on the repulfion occafioned by electricity; but it has the additional advantage, that the quantity of this repulfion is not only afcertained by a dial fhewing how high the arm that is repelled is raifed by certain charges, but also by the weight required to counterbalance the repulfion of the charge.

Mr. Brook is of opinion that, by means of this inftrument, it will be poffible to ascertain the charge or quantity of coated furface that is required to produce any given electrical effect, fuch as melting a wire of certain dimenfions, killing certain animals, &c.; and that this electrometer will be found to fpeak a much more general and intelligible language than any hitherto ufed.

There must be fome capital omiffion in the printing of this Paper, as moft of the figures in the plates which have letters of reference,

reference, are not explained in the text, by which means a great part of the conftruction of the apparatus becomes unintelligible.

ΑΝΑΤΟΜΥ.

Art 23. Account of the Organ of Hearing in Fish.

Hunter, Efq. F. R. S.

By John

Had Mr. Hunter ever acquiefced in the affertion of moft anatomifts, that fish have no organs of hearing (which feems however not to have been the cafe), he would have relinquifhed that opinion, on feeing one day a large fhoal of fish fo fenfibly affected by the report of a gun, as to fly inftantly to the bottom of the water, and feek fhelter in the mud. Our Author has fince diffected a variety of thofe organs, and made preparations of them, which have been exhibited for feveral years paft in his collection. He does not take upon him to give, in this paper, a full defcription of this organ in any one fish, or of the varieties in different fish, but only attempts to convey an idea of the organ in general.

In all the fpecies of fifh, it is placed on the fides of the skull, which however does not form any part of the organ, as it does in quadrupeds, birds, &c. The parts furrounding it are always cartilaginous, both in the fpecies whofe whole fkeleton is cartilaginous, as the ray, &c. and in thofe whofe fkeleton is boney. In fome, as in the falmon, cod, &c. it is within the cavity of the fkull. It grows with the fifh, and is always proportionate to the other parts, which is not the cafe in moft other animals, where it is almoft as large in the foetus as in the adult. Its conftruction varies fomewhat in different orders of fish, but in all it confifts of three curved tubes, forming each about a semicircle; two of these tubes are perfectly fimilar, and may be called a pair;-their pofition, or rather the plane of their curvature, is perpendicular; they unite at the top, and there the whole organ is connected, in most species, with an external meatus, which in fome is not perceptible. The two other extremities of these perpendicular tubes open into the two ends of the third tube, the plane of whofe curvature is horizontal. At each of these three junctions the tubes are fwelled, and open, in fome claffes, into a canal, as in the cod, falmon, ling, &c. and in others into a pretty large cavity, as in the ray, &c. In the jack, there is an oblong bag, or blind procefs, added to the above canal. In the cod, the three junctions of the tubes ftand upon an oval cavity, and in the jack are two of these cavities. In this cavity there is ufually a bone or bones; in the jack, where there are two cavities, there are in one of them two bones, and in the other one. In the ray kind, this cavity contains only a chalky fubftance.

The nerves of the organ proceed from the brain, and seem to terminate on the fwelling of the femicircular tubes. They do not appear to penetrate into the infide of the tube, as is fuppofed

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to be the cafe in quadrupeds; whence Mr. H. fufpects, that the inner coat of these tubes is not nervous, but a kind of internal perioftæum.

Art. 27. d Microscopic Defcription of the Eyes of the Monoculus

Polyphemus Linnæi. By William André, Surgeon.

This cruftaceous animal, which is known on the coaft of America, and in the Weft Indies, by the name of King Crab, is diftinguished from all its congeneric fpecies, by having four eyes instead of two; and thofe not placed on flems, as they are on other crabs, but inferted in the fhell, or, as Linnæus expreffes it, tefte innati. Two of them are much faller than the others. The large hell of this fith, which is fomewhat fimilar to a crefcent, being divided tranfverfely into two, the larger eyes are fituated nearly at the centers of these two pieces, and the fmaller ones close to the divided edge, near the fore part of the fhell. The former, viewed in a microscope, are found to confist of a great number of small transparent amber-like cones (about 1000 in each), which have in general an oblique direction, except a few in the middle which are perpendicular. The center of each of them being the moft tranfparent part, and that through which the light pafles. The perpendicular or central cones are beautifully illuminated at their points; it appears hence, that the cones are thus difpofed in various directions, that a certain number of them may receive light from whatever point it may iffae..

On a clofer inspection of thefe cones, which at first appeared to be tubes, it was found that they are folid tranfparent bodies, divided tranfverfely by two or three internal diaphragms or partitions; and in one inftance, it was found that the external lamina were feparated from an internal layer of a foft texture. As thefe animals are known to caft their fhells every year, and as the cornea or external coats of the eyes, which are a part of that fhell, must be depofited with it, it is conjectured that the internal layer, juft mentioned, contains the rudiments of a future

cornea.

The fmaller eyes confift of an oval transparent horny plate, of an amber colour, in the center of which ftands a fingle cone, through which the light pafies.

The MATHEMATICAL Papers, in a future Article.

ART. VII. Sermons on several Subjes. By the Right Rev. B. Porteus, D. D. Bishop of Cheller. 8vo. 5s. Boards. Cadell, and Payne. 1783.

OOD fenfe, an eafy and natural ftrain of argument, delivered in a chatte, accurate, and elegant ftyle, abounding with reflections, fometimes folemn, and fometimes pathetic; the whole animated by a fpirit of warm but rational piety, which

aims at the improvement of the heart and life-thefe, if we mis, take not, are the characteristics of the prefent difcouries.

Some may think them fuperficial, because they are not obfcure: others may deem them unaffecting, because they are not enthusiastical: and there is a third clafs of readers who will grow tired of them, because they affect no novelties of fentiment, nor attempt to elevate or furprife by rare metaphors, or those fingu larities of thought and expreffion, of which fome preachers have availed themfelves, as expedients to ftimulate a vitiated appetite. The Bishop of Cheiter is fuperiour to fuch arts as these. He confiders the beauty of truth as fufficiently energetic, when fimply difplayed, to effect its own ends, without borrowing aid from phantaftic and glittering ornaments, He reverences religion with too awful a respect, to treat it with an indecorous Freedom; and loves it with an affection too ardent, to be indifferent to its interefts, or carciefs and unconcerned in the difcharge of its duties.

The first fermon, on the Love of God, is an excellent compo fition. It delineates the true principles and genuine effects of this great duty of Christianity, and guards it against the extremes of apathy and enthusiasm. "The love of car Maker is neither a meer, unmeaning, animal fervour, nor a lifeless, formal worship and obedience. It conlifts in devoutnefs of heart, as well as purity of life; and from a comparison of the text (Matth. xii. 30.) with other paffages of Scripture, we may define it to be, fuch a reverential admiration of God's perfections "in general, and fuch a grateful fenfe of his infinite goodness "in particular, as render the contemplation and the worship of "him delightful to us; and produce in us a constant defire and "endeavour to please him in every part of our moral and reli"gious conduct." This is it that the Scriptures mean by the love of God, and it is nothing more than what every man may, if he pleafes, very easily acquire. It is not a new perception of which we never experienced any thing before. It is not an unintelligible, myfterious, or fupernatural impreffion upon the foul. It is only a purer degree of that very fame affection which we frequently entertain for the most worthy of our own species.

The fecond fermon, on the Causes of Unbelief, from John iii. 19. hath been already published; -as have allo the eighth, Tit. ii. 6. the eleventh, Jer. xviii. 11.part of the thirigenth, Luke ii. 14. and the fourteenth, 2 Tim. ii, 4.--though they are here reprinted with confiderable alterations and corrections.'

The fubjects of the other fermons, now for the first time publifed, are the following:

Serm. III. and IV. The poffibility of refifting temptation afferted and proved. In thefe fermons the Bifhop vindicates the

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