When the whole apparatus was put in use, the phial was filled with cold pump water, in a pneumatic tub, then inverted, and the species of air to be employed was let up into it to the quantity of about eight ounces. The subject for experiment being applied to, or fastened upon, the top of the cork, the stand was placed on the tea-saucer, and then introduced, under the water, into the phial con➜ taining the air. The whole apparatus, being now supported by the tea-saucer, with water in it, was deposited in the laboratory for experiments on light. By this contrivance, the experiments were made in about eight ounces of air, by measure, confined above two ounces of water.'

The experiments of the first section relate to the effects of common or atmospherical air on spontaneous light. In these investigations, Dr. Hulme employed herring, mackerel, rotten wood, and glow worms; and he concludes, 1st, that objects which abound with spontaneous light in a latent state, such as herring, mackerel, et similia, do not emit it when deprived of life, except from such parts as have been some time in contact with the air; and, 2dly, that the blast of bellows does not increase this species of light, as it does that which proceeds from combustion.

The effects of oxygen gas, or vital air, on spontaneous light, were then examined; and the results of these experiments prove that oxygen gas does not act on this kind of light, so as to render it much more vivid than it is in atmospherical air; which is contrary to what some authors have alleged.

We next find some experiments made with azotic gas ob tained by different processes; and here it is certainly curious that (according to Dr. H.) azotic gas, which is incapable of supporting light from combustion, should prove to be favourable to the spontaneous light which is emitted from fishes; sq much so, as even to preserve its existence and brilliancy for some time, when applied on a cork: but it prevents the flesh of the herring and the mackerel from becoming luminous, and extinguishes the light which proceeds from rotten wood.

From the experiments made with hydrogen gas or inflam mable air, we find that, in general, it prevents the emission of spontaneous light, and also extinguishes it when emitted: but, at the same time, it does not hinder its quick revival, when the subject of the experiment is again exposed to the action of atmospherical air, although the light may have been in an extinguished state during a considerable time.

Carbonic acid gas, or fixed air, has also an extinguishing property, with respect to spontaneous light: but, in general, the light returns, if the object of experiment be taken out, and exposed to the open air.

Sulphurated

2.

Sulphurated hydrogen gas extinguishes spontaneous light much sooner than carbonic acid gas; and, in general, the light returns much more slowly, when the subject is exposed to atmospheric air.

Nitrous gas totally prevents the emission of light, and quickly extinguishes that which has been emitted. Dr. Hulme likewise observes that the luminous objects, which had been under its influence (except the glow worm,) did not experience a revival of their light, when taken out, and kept for some time in common air.

The effects of a vacuum were next examined; and from two experiments, it appears that the light of rotten wood and of herring was diminished in proportion as the air was extracted from the receiver of an air pump in which they were placed; and that both of these substances gradually recovered their luminous appearance, in proportion as air was again admitted.

The paper concludes with some experiments and observations on solar light, when imbibed by Canton's phosphorus ; and the author infers from his trials with this substance, 1st, that the imbibed light is rendered more vivid by a mode. rate degree of heat: 2dly, that the imbibed light is extinguished by a great degree of heat; and, 3dly, that the imbibed light, after having been in a latent state, is excited and rendered Juminous by the agency of heat.

An experiment to ascertain the effects of cold on imbibed light is also related; the result of which seems to prove that cold possesses an extinguishing property. Dr. Hulme then

says; From these experiments, compared with those recited in my former paper on spontaneous light, it appears that solar light, when imbibed by Canton's phosphorus, is subject to the same laws, with respect to heat and cold, as the spontaneous light of fishes, rotten wood, and glow worms.'

Experiments on the Chemical Production and Agency of Electricity. By William Hyde Wollaston, M.D. F.R.S.-In consequence of the doubt which has been entertained by many persons, whether the power of M. Volta's Pile arises from the chemical action of the interposed fluid on the metallic plates, or, on the contrary, whether the oxidation itself may not be occasioned by electricity, set in motion by the contact of metals that have different conducting powers, Dr. Wollaston was induced to make some experiments, from which he infers that the oxidation of the metal is the primary cause of the electric phænomena observed.-After having related other experiments, which seem to prove that the chemical agency of common electricity is the same with the power excited by chemical means,

he

he proceeds to observe that he has been at some pains to shew, that at least a very close imitation of the Galvanic phænomena can be produced by common electricity. He then remarks

that

It has been thought necessary to employ powerful machines, and large Leyden jars, for the decomposition of water; but, when I considered that the decomposition must depend on duly proportioning the strength of the charge of electricity to the quantity of water, and that the quantity exposed to its action at the surface of communication depends on the extent of that surface, I hoped that, by reducing the surface of communication, the decomposition of water might be effected by smaller machines, and with less powerful excitation, than have hitherto been used for that purpose; and, in this hope, I have not been disappointed.

Exper. 6. Having procured a small wire of fine gold, and given it as fine a point as I could, I inserted it into a capillary glass tube; and, after heating the tube, so as to make it adhere to the point and cover it in every part, I gradually ground it down, till, with a pocket lens, I could discern that the point of the gold was exposed.

The success of this method exceeding my expectations, I coated several wires in the same manner, and found that when sparks from the conductors before mentioned were made to pass through water, by means of a point so guarded, a spark passing to the distance of of an inch would decompose water, when the point exposed did not exceed 7 of an inch in diameter. With another point, which I estimated at a succession of sparks of an inch in length, afforded a current of small bubbles of air.

C

• I have since found, that the same apparatus will decompose water, with a wire of an inch diameter, coated in the manner before described, if the spark from the prime conductor passes to the distance of of an inch of air.

Exper. 7. In order to try how far the strength of the electric spark might be reduced by proportional diminution of the extremity of the wire, I passed a solution of gold in aqua regia through a capillary tube, and by heating the tube, expelled the acid. There remained a thin film of gold, lining the inner surface of the tube, which, by melting the tube, was converted into a very fine thread of gold, through the substance of the glass.

When the extremity of this thread was made the medium of communication through water, I found that the mere current of electricity would occasion a stream of very small bubbles to rise from the extremity of the gold, although the wire, by which it communicated with the positive or negative conductor, was placed in absolute contact with them. Hence it appears, that decomposition of water may take place by common electricity, as well as by the electric pile, although no discernible sparks are produced.

The appearance of two currents of air may also be imitated, by occasioning the electricity to pass by fine points of communication on both sides of the water; but, in fact, the resemblance is not complete; for, in every way in which I have tried it, I observed that each

wire

2

Case of a young Gentleman, who recovered his Sight when seven Years of Age, after having been deprived of it by Cataracts, before he was a Year old; with Remarks. By Mr. James Ware, Surgeon. This cure was effected on one eye by the couchingneedle; with which, the cataract being of a soft consistence, and not capable of being depressed, a large aperture was made through the capsule; and thus the crystalline was brought into contact with the other humours: a considerable part of it coming forwards, and shewing itself directly under the cornea. In a few days, the opaque matter was wholly absorbed, the pupil became clear, and the patient recovered his sight with the couched eye. If, however, in addition to the opacity of the crystalline humour its capsule be also opaque, either in its anterior or posterior portion, or in both, (which circumstance cannot be ascertained before the operation,) and in consequence of this the operation above stated should not prove successful, it will not preclude the performance of extraction afterward, if this measure be thought adviseable. The operation of the couching needle was repeated on the other eye, in a month's time after the former, but without success; owing, it is conjectured, to an opacity in the capsule, which was incapable of being absorbed.

Farther Observations on the Effects which take place from the Destruction of the Membrana Tympani of the Ear, with an Account of an Operation for the Removal of a particular Species of Deafness. By Mr. Astley Cooper.-It had been made apparent in a former paper, and is confirmed in this, that an aperture in the Membrana Tympani does not diminish the power of the ear; and that even a complete destruction of the membrane is not followed by a total deprivation of the sense of hearing, as is commonly supposed. Mr. Cooper now proposes to try the operation of puncturing the membrana tympani, in the deafness which arises from an obstruction of the Eustachian tube produced by pressure of enlarged tonsils, by an ulcerous sore throat, by venereal ulcers, by extravasation of blood, by stricture in the tube, &c. in all of which cases, it has been successful. This practice is founded on principle. Like a drum, the tympanum of the ear cannot perform its office unless there be a free passage for air into the cavity; and as the air passes from the throat to the ear by the Eustachian tube, the membrana tympani is placed between two portions of air, the one contained in the meatus, the other in the cavity of the tympanum. Accordingly, if the Eustachian tube be obstructed, the air confined in the tympanum being unable to yield, the membrana tympani must cease to vibrate; and thus, sound being no longer conveyed

T

to

to the interior parts of the organ, a permanent deafness would

ensue.

This volume closes with the usual Lists, Index, &c.

from p. 302. Pear. See pp. 295,296,302.

ART. XIII. A Tour through the Batavian Republic during the latter Part of the Year 1800: containing an Account of the Revolution and recent Events in that Country. By R. Fell. 8vo. pp. 400. 8s. 6d. Boards. R. Phillips. 1801.

ON account of the new political aspect in which the country must be viewed, a tour through the United Provinces, or (to give them their revolutionary title) the Batavian Republic, at a period in which the journey here recorded took place, must possess greater interest, and demand more attention, than works. of this kind ordinarily involve and deserve. The opinions of an individual, however, respecting the merits of any great political change, are to be received with caution, since man not only reasons but observes according to his prejudices; and consequently, the opportunity of being an eye-witness to the state of affairs bestows a doubtful advantage, and forms an equivocal title to superior credit. In our selection, therefore, of such parts only of this work as relate to the political situation and characters of the Batavian Republic, we have been guided more by the superior interest which they derive from the novelty of the subject, than from any conviction that they contain an unerring accuracy of observation, or a decisive rectitude of opiYet it is but justice to the author to declare, that, though the political bias of his mind is sufficiently evident, he does not appear to be strongly warped by any inveterate prejudice, either in his ideas or his remarks.

Mr. Fell, we learn, was taken prisoner on his coasting passage to London from the north of England, by a French privateer, and was carried into the Briel:-but, having obtained passports from the Batavian government, through the means of the French General, Chorie, he was enabled to employ the period of his detention in seeing all that was most remarkable in the United Provinces. Speaking of the state of commerce in the Batavian Republic, he says:

According to the report of a very intelligent and judicious merchant, whose acquaintance I have had the good fortune to obtain, Rotterdam does not at present enjoy a tenth part of the commerce which she possessed before the French invasion, and the interruption of her intercouse with Great Britain. Before the war, it sometimes happened, that three hundred English vessels were seen at one time within the port of Rotterdam; and this number was certainly exceeded by the ships belonging to the place and those of other nations. At present the number of neutral vessels in the harbour do not exceed REV. MARCH, 1802. X

fifty,