refer the Reader to the article itself for an account of the manner in which the Author was led to discover, that, in this cafe, the electric fluid fuddenly enters, and, as to fenfe, inftantaneoufly leaves the infulated body, without making any fenfible alteration in the electricity natural to it.

Article 25, De Atmofphæra electrica, Joannis Baptiftæ Beccariæ, R. S. S. ex Scholis piis, ad Regiam Londinenfem Societatem Libellus.

By the series of experiments contained in this paper, one of the most fingular and important properties of the electric fluid, fucceffively obferved and explained by Mr. Canton, Dr. Franklin, and Mefirs. Wilke and Epinus, is completely and} fatisfactorily demonftrated. This law, which throws fuch light on the properties of the electrical fluid, and on the phenomena of the Leyden Vial in particular, is, that the electric matter being accumulated in any body, repels that naturally exifting in other bodies in its neighbourhood, and thereby renders them negatively electrical: and this effect it produces, although fubftances intervene through which the electric fluid itfelf does not pafs. Indeed, all our experiments concur in afcertaining this fingular fact; that though glafs, air, and other non-conducting fubftances, are impermeable to the electric matter itself, yet they are pervious to the action of that fluid; either by means of fome vibration, or other peculiar modification of their own particles, or by the intervention and agency of fome fubtile and unknown medium. When we fay that the electric fluid, condenfed on one fide of a plate of glass, repels that which naturally belongs to the oppofite furface, though itself is incapable of paffing through the fubftance of the glass; we do not mean that the electric, or any other matter, can immediately act on other matter in diftans, or where it is not: for that would be abfurd. The impermeability of the glafs, and the repellent power of the electric fluid through it appear to be matters of fact, fatisfactorily eftablifhed by experiment; and it is the bufinefs of philofophers to difcover the particular means or media, by which its action is communicated through bodies, which refift its actual paffage through them.

The greater part of the experiments, contained in this dif fertation, prove this property of the electric fluid, as exerted through air; and particularly, that one furface of a plate of air cannot receive an additional quantity of electric matter, unless a paffage is given for the efcape of the natural electricity of the contiguous frata in.o the earth. We fhallbriefly defcribe one of thefe experiments. The Author electrifies, pofitively, for exmaple, a hollow metal cylinder, which he terms the electrical well. Into this he lets down another fmaller cylinder, completely infulated, which he calls the bucket. We should obferve, that it

is a matter of indifference, whether the bucket comes in contact with the bottom or fides of the electrified well or not. On drawing it out from thence, it is found not to have contracted any fenfible degree of electricity: though had it touched any part of the outside, it would undoubtedly have acquired pofitive electricity. He now repeats the experiment; but takes care that the bucket fhall not touch the bottom or fides of the well; and, while it continues there, he brings the knob of a brass rod near the bucket. A fpark is now feen to pafs between them. This fpark does not proceed from any electricity communicated by the electric well to the bucket; but is evidently the native fire belonging to the latter, driven out of it, through the rod, into the earth, by the electric matter in the ftratum of air contiguous to the inner furface of the well, acting through the cylindrical plate of air interpofed between it and the bucket: for though the well is charged with positive electricity, the bucket, on being drawn out, is found to be negatively electrified. We need not make any comment on this experiment; which the Author afterwards diverfifies.

Several corrollaries follow, which are deduced from these experiments. We fhall mention only one, drawn from that which we have now related, and which is, at leaft, fanciful and ingenious. Confidering the minute and evanefcent pores of natural bodies as fo many electric wells, a plaufible reafon may be hence affigned, why the quantity of electrical fluid thrown upon bodies, in our experiments, is found to be proportionable to their furfaces only, and not to their bulks or maffes. The pores of bodies, like the cavity of the well, appear to be devoid of electric matter; while the furface of the intire body is analogous to the outfide of the well; and, like it, for the reafons above suggested, can receive and communicate electricity.

In the 17th article Capt. J. L. Winn gives Dr. Franklin an account of the appearance of lightning, during a ftorm in the night, on a conductor (formed of a chain of copper wire extended from the top of the mainmaft of his fhip down to the water) one of the links of which had been broke; as he accidentally difcovered by means of the stream and sparks of electric fire, which appeared in the place of the interruption. He publifhes this obfervation, in expectation that it may have greater weight with fome feamen, whofe neglect of this eafy prefervative he justly condemns, than all the reasonings of the electricians.

* Dr. Franklin first discovered this fingular property in an elec trified cup. Dr. Priefley's experiments and obfervations upon it may be feen in the History of Electricity, page 731, 1ft edition.

In

In the 46th article Mr. Swinton defcribes the phenomena attending a very remarkable meteor, of the Aurora borealis kind, feen at Oxford on October 24, 1769; and which, we shall add, was observed by us, with nearly the fame appearances, in a distant part of the island. Article 14 contains obfervations on the state of the air, winds, and weather, in Hudson's Bay, in the years 1768 and 1769, by Meffrs. Dymond and Wales and in articles 20 and 21 are contained meteorological obfervations made in 1769 at Bridgewater and Ludgvan, by Dr. Jeremiah Milles, and Dr. Borlafe.

MISCELLANEOUS ARTICLES. Difficulties in the Newtonian Theory of Light, confidered and removed. By the Rev. S. Horsley, LL. B. F. R. S.

The difficulties here referred to are thofe propofed by Dr. Franklin, in one of the letters contained in his collection of Papers on Philofophical Subjects, published in 1768. On a fuppofition that our fenfations of the folar light are not caused by the preffure or undulations of a fluid diffused throughout the universe, but are excited by a matter continually emitted from the furface of the fun, with a prodigious velocity, and in all directions; the Doctor afks, whether the fmalleft conceiveable particle of light muft not, with fo rapid a motion, acquire a momentum or force exceeding that of a twenty-four pounder difcharged from a cannon? Muft not the fun, he adds; diminish exceedingly by fuch a waste of matter, and the planets recede to greater distances, in confequence of the leffened attraction? And yet these particles, fuppofed to move with this immenfe velocity, are found incapable, as he obferves, of driving before them, or even of giving the leaft fenfible motion to, the lighteft duft: the fun too, there is reason to believe, continues of his original dimenfions, and his attendants move in their ancient orbits.

Mr. Horfley, in a former publication, had occafion to inquire what the force of motion in the particles of light, fuppofing them to be actually emitted from the fun, could poffibly amount to, if calculated at the utmoft. Suppofing, for reasons which we omit, that the particles of light are of fo fmall a fize, that the diameter of each spherule does not exceed one millionth of one millionth of an inch; and allowing the denfity or fpecific gravity of each particle to be even three times greater than that of iron, and its velocity to be fuch as has been generally fuppofed, he arrives at this general conclufion, that the force of motion in each fingle particle emitted from the fun, is lefs than that in an iron ball of a quarter of an inch diameter, moving at the rate of lefs than an inch in 12,000 millions of millions of Egyptian years;'-in fhort, that it is a force much

inferior

inferior to any that art can create. He afterwards fhews that the stroke which the retina of the eye fuftains, by the direct impulfe of a cylinder of the fun's rays tranfmitted through the pupil, (fuppofing its diameter to be To of an inch, and the emiffion to be at its maximum) does not exceed that, which would be given by an iron fhot of the fame dimenfions, moving at the rate of little more than 16 inches in a year.

This question has been agitated formerly, but no where, we believe, in fo complete and accurate a manner. Muffchenbroek, in particular, has curforily difcufled this fubject [in his Introductio ad Philofophiam Naturalem] on data different from those of this Author. From the refult of his calculations he is led to question whether all the globules conftituting a ray of light, extending from the fun to the earth, that is, a ftring of fpherules 24,000 femi-diameters of the earth in length, would weigh a fingle grain.

The Author next proceeds to confider the lofs of fubftance which the fun may be fuppofed to have fuftained, in confequence of the continued or rather fucceffive emanation of fuch particles. He fhews that, fuppofing 951,100 emissions were to be made every fecond, of all the luminous particles, of the magnitude above affumed, that would have room to lye upon his furface at once; this emanation would not be attended with any fuch waste of his fubftance, as would vifibly contract his diameter, or fenfibly enlarge the orbits of the planets, in many millions of years. According to his calculations, the space of 385,130,000 Egyptian years would be required to produce, in confequence of fuch waste, a diminution of the fun's apparent diameter, equal to the 1900th part of a fecond. These are fome of the principal refults of the Author's fuppofitions and calculations, which are equally ingenious and elaborate, and appear more than fufficient to obviate the objections that have been made to the actual emiffion of light, founded on an apprehenfion of the enormous lofs of fubftance fuppofed to attend it in the luminous body.

Of the three remaining articles of this volume, though deferving of a more particular notice, our limits at prefent oblige us to give only a very curfory account. The 8th contains a well authenticated and pleasing relation, by the honourable Mr. Barrington, of the early and uncommon difplay of talents, in the cafe of young Mozart; who, when he was little more than four years old, was not only capable of executing leffons on the harpfichord, but like wife compofed fome in an eafy style and taffe, which were much approved of." At the age of eight, he was heard with aftonishment in this kingdom; and, as we are informed by a late traveller, in a work published after this pa

per

per was written*, his premature performances have fince excited the admiration even of Italy; where they have procured him the honour of the order of the Golden Spur, conferred upon him by the present Pope.

The 10th Article contains an account of fome improvements made by Mr. Fitzgerald, in the new wheel barometer invented by him, and defcribed in the 52d volume of the Tranfactions. This inftrument not only diftinctly fhews a rife or fall of the mercury equal to the 600th part of an inch; but likewife, by means of regifters placed clofe to the index, marks the greatest variations in the motion of the quickfilver, which happen during the absence of the obferver, or in the night. In the 28th, or remaining article, Dr. Watfon, late Chemical Profeffor at Cambridge, relates feveral curious experiments made by him, on the various phenomena attending the folution of falts in water; particularly with a view to inquire into the truth of the commonly received opinion that, in the procefs of diffolution, faline fubftances are abforbed or received into the pores of the folvent, without augmenting its bulk. The Author's experiments however seem fully to juftify a contrary conclufion.

ART. IX. The Hiftory of the famous Preacher Friar Gerund, &c. concluded.

N the clofe of the first volume, of which we gave an account in our laft Review, Friar Gerund commences what is called Sabatine Preacher, and is engaged to pronounce a difciplinant exhortation on account of a proceffion for rain, in the town where the convent ftood. Notwithstanding the friendly and judicious admonitions he had received, he determined to purfue his own views, aided by the profound and learned counfels of the Predicador Mayor. We have a humorous account of the compofition of this difcourfe, with a copy of the difcourfe itself; concerning which, we fhall only obferve, that it produced fome warm, animated, and honeft reproofs from the Father Mafter Prudentio.

The fecond volume begins with informing us, that Anthony Zotes, the father of our hero, who was now conftituted majordamo of the facrament (after having heard the exhortation abovementioned) appointed his fon to preach the fermon on this occafion at Campazas; to which requeft the fuperior of the convent unwillingly yielded affent. This was the young Friar's first fermon, as the difciplinant-exhortation was not to be dignified with that name. He had fome debates with himfelf about the forming of this difcourfe; for he had not forgotten

* Dr. Burney's Prefent State of Mufic, page 228.

the