the accustomed phrafeology. He found the term, air, generic, and he retained it; applying it to each of the newly obferved elaftic fluids, with the addition only of fuch an epithet as either indicated its quality, or denoted the particular fubftance from, or by means of which it was procured. As the fenfe in which he thus employed the term air, was precifely explained by him, and the term itself only used to diftinguish these fluids from vapours condenfable by cold; we cannot fee any inconvenience likely to follow the retaining it, or, in particular, that any one could be in danger of being misled by the ufe of it:-efpecially as, after all our discoveries on these fubjects, the nature of fome of thefe fluids,-even of the AIR itself, is not yet perfectly known; and further experiments are perhaps ftill wanting to enable us to pronounce, What is AIR, and what is not? Our ingenious reformer of the old phrafeology has not, we think, been perfectly confiftent in one part of his new nomenclature. To the elaftic fluids above mentioned, he has given the title of gases, in order to distinguish them from the AIR properly fo called; because, as he alleges, they are very different from it in moft of their properties; and the giving them the fame name is as great an impropriety as if all liquids were confounded under the name of water. In conformity to this diftinction, the term, gas, ought not, under any modification, to have been applied to the AIR. The Author nevertheless, in his chapter on common or refpirable air, has, befides its usual appellation, given that fluid the title of atmospherical GAS.-But to proceed from words-on which we have perhaps dwelt longer than becomes philofophers—to things: though, as critics likewise, we have a right to watch over language, as well as matter; especially when an innovation is presented to the court. From the new matter contained in this performance, we shall only felect an interefting original experiment of the Author's, relating to the production of dephlogisticated air (or as he terms it, deflagrating air, or gas), through the means of the vitriolic acid. We have formerly given an abstract of Dr. Priestley's process*, in which he calcined three separate portions of red lead, combined with the three mineral acids; and procured no dephlogifticated air except from that parcel which was treated with the nitrous acid. The author has met with a different refult: we shall therefore transcribe part of the account which he gives of his process, in his own words. By applying vitriolic acid to red lead, I have obtained a large quantity of air, which feems to poffefs all the properties of the pure factitious air, produced by means of nitrous acid. See M. Review, vol. liv. February 1776, p. 110. K 2 EXPE 郎 EXPERIMENT. • Forty-eight penny weight of red lead were put into a long necked retort, the contents of which were ten cubic inches; and upon this red lead twenty-four penny weight of oil of vitriol, were poured. The nofe of the retort was then immerfed under water, and over it an inverted jar filled with water was placed. The mixture of red lead and oil of vitriol became very hot, and ten cubic inches of air were foon thrown into the jar, without the application of external heat. Upon applying the flame of a lamp to the bottom of the retort, bubbles of air paffed copiously into the jars, which were fucceffively changed, that the air received at different times of the operation might be examined. The quantity of air which had been expelled from the above mixture of red lead and vitriolic acid, was found to be thirty-fix cubic inches, after the proper allowances for the air contained in the retort had been made. • A candle burnt very well in the air of the first jar, most of which was common air that had been expelled by the heat and vapours of the mixture. A lighted candle being put into some of the air of the fecond and fucceeeding jars, burnt with a very vivid white flame, and deflagrated in the fame manner as in the air produced from nitrous acid.' The author proceeds to fhew, by other trials, that the (dephlogisticated) air thus produced from red lead, by means of the vitriolic acid, had the fame properties, and poffeffed them in the fame degree, with that obtained by Dr. Prieftley, from the fame and other fubftances, through the means of the nitrous acid:that it exhibited as great a diminution on the admixture of nitrous air-that it caufed a much greater explosion, when mixed with inflammable air, than is effected by common air:-and that its purity was further evinced by the extraordinary length of time in which a mouse lived in it. The Author further obferves, that the preceding process has this advantage over that in which the nitrous acid is employed for the production of dephlogisticated air; that the air thus procured, is not liable to be rendered impure, and even noxious, by the admixture of nitrous air; as fometimes happens when the nitrous acid is employed:-that the materials likewife are cheaper; and that the process accordingly feems preferable for any medicinal or economical purposes to which a pure deflagrating air fhould be hereafter applied.'-Care however fhould be taken, that the minium and oil of vitriol fhould be perfectly pure. The Author found, as Dr. Priestley had. before experienced, that no air could be thus obtained, on ufing the marine acid; and he afcribes the Doctor's having failed to produce dephlogisticated air, from minium and the vitriolic acid, to his having dried the mixture before he attempted to procure air from it; on a fuppofition that the greatest part of the air had been expelled during the exficcation; much less heat being neceffary for the production of air in the process with oil of vitriol, than in that where the nitrous acid is employed. We have dwelt particularly on this experiment, as it appears to be of importance towards afcertaining what are the real conftituent principles of atmospherical air, and feems to evince, that the nitrous acid is not neceffary to the conftituance of that fluid. The following doubts, however, occur to us on this head, which we could with the ingenious Author would remove by diverfifying the experiment. In the first place, we obferve that only thirty-fix cubic inches, that is (as we grofsly eftimate) about eighteen ounce meatures of air were procured from this mixture of forty-eight pennyweight of minium with vitriolic acid. There may be reafon to fufpect that the whole of this air might be originally contained in the minium, and might only be expelled from it by heat, affifted in its operation by the action of the vitriolic acid. To tender the experiment more decifive, we would propofe that the minium fhould be again treated with fresh oil of vitriol; in order to difcover whether, in conjunction with that acid, it would continue to furnish dephlogisticated air, toties quoties; as is the cafe with this and all other carthy fubftances, when the nitrous acid is combined with them. We fhall only add that, from Dr. Priestley's account of his experiments with minium and the three acids, to which the Author refers*, it appears that the particular minium which he employed, and which gave him dephlogiflicated air when the nitrous acid was added to it, contained originally very little air; or at leaft yielded a very fmall quantity, and with great difficulty, when expofed alone even to the intenfe heat of a large burning lens. He confidered this fpecimen therefore as being in a very favourable ftate for the defign which he had in view, of difcovering what would be the refult of combining these three acids with it. Some ingenious fpeculations and conjectures on the theory of Gafes' terminate this performance, the perufal of which we recommend to those who may with only to acquire a general knowledge of the fubjects treated in it. At the fame time it will ferve as an useful remembrancer to those who are already converfant IN THIS BRANCH OF KNOWLEDGE. B..Y * See Dr. Priestley's Obfervations on Air, vol. ii. p. 52; or our account of the experiments in our volume above referred to. ART. VII. A Letter to Benjamin Franklin, LL. D. F. R. S. In which his Pretenfions to the Title of Natural Philofopher are confi dered. 8vo. 1 S. Bew. 1777. WE E Reviewers are obliged, from the nature of our office, to keep all kinds of company; but we can scarcely recollect our having met with a more empty, and at the same time a more folemn coxcomb than the prefent. In the course of his twenty-four pages he makes a mighty parade about Newton, the fcience of magnitude and number, and demonftration, and all that. He gives us to underftand, that philofophy-a lady, as he represents her, of the highest quality-has of late years fhamefully demeaned herfelf by keeping very low company;-meaning Dr. Franklin, and the fwarm of philofophers that we meet with every where, of the fame rank and qualifications' with him-men, in fhort, wholly illiterate,' who can neither, understand a demonftration, or computation;' but may neverthelefs be qualified for blowing up bladders in an air pump, or for drawing sparks from an electrical machine:'-'fit enough," he owns, to be employed as hewers of wood, and drawers of water, for the fervice of the temple; though by no means proper to be admitted to minifter at the altar.'-But hear the wife motives which this folemn-what fhall we call him?-affigns for his prefent addrefs to Dr. Franklin. It may probably be afked, why this letter makes its appearance now, after the world have been so long in poffeffion of your writings? The truth is, my acquaintance with them commenced but very lately; for, in the first place, I am not very fond of novelties;-[An excellent character this man gives of himself, as a philofopher!] and, fecondly, you may very eafily believe that a man who has spent the greatest part of his time in the study of Newton's principles, and the fciences neceffary for understanding that book, might hear of people rubbing glass tubes, without any violent curiofity about the confequences. But more efpecially if he had perfuaded himself that Newton reaped fo compleat a barvest―[What, among the glafs tubes in particular?] as to leave but poor gleanings for pofterity.' 6 With the fame mock dignity and confidence this ftately wight declares to the world, that felf-taught philofophers are truly no favourites of his; and that a regular education'—he— does not point out at what univerfity-is abfolutely neceffary. wards the making any ufeful improvements in fcience. You, yourself,' fays he, addreffing himself to Dr. Franklin, furnish us with many inftances of your low breeding; and, amidst all your philofophical parade, it is ealy to dilcover the worker at the prefs. It was our intention, after giving a patient audience to this pompous fribble, to have difmiffed him fomewhat civilly: but, on hearing this laft dirty allufion, our devil in waiting was immediately called in, and ordered by our whole corps, graduates and irregulars, to turn him out head and shoulders. B..y. ART. VIII. Remarks on Mr. Forfter's Account of Captain Cook's last ON N ne repouse point la VERITÉ fans bruit, &c."-faid Mr. Forfter, in the frontifpiece of his Voyage, after De Miffy; and we repeated the motto after him, in our account of his work, as being excellently adapted to travellers and voyagers in particular; and to the purport of which we then believed that Mr. Forfler had bona fide conformed. But alas! in these days there is no trufting either to frontispieces or profeffions; as appears too evidently from the contents of the publication now before us in the title-page of which Mr. Wales brings Mr. Forster's motto in judgment against him, as an appofite introduction to the enfuing copious account of the mifreprefentations and calumnies with which he charges his brother voyager. In that publication, fays Mr. Wales, Dr. Forfter + has, in many places, involved the whole fhip's company, officers and men, in one univerfal cenfure of ignorance, brutality, cruelty, wantonness, and barbarity, and has, at one time or other, taken care to brand every one of us with fuch crimes, and ftigmatize us with fuch epithets, as would, were they true, render us undeferving the leaft confidence.'-Dr. Forfter's conduct on this occafion is reprefented by Mr. Wales, as having been influenced by revenge, to which the former fomewhere gives the appellalation of a most useful and facred paffion.' The motives or • Monthly Review, vol. lvi. April, 1777, p. 266. + Mr. Wales confirms the fufpicion which might naturally be entertained by an attentive reader of the work in queftion, that Dr. Forfter molt probably had the principal hand in drawing it up.The whole book, fays he, is written with fo much arrogance, felfconfequence, and afperity; and the actions of perfons are decided on in fo peremptory and dogmatical a manner, that I cannot fuppofe it to be the production of a young man fcarcely twenty years of age. Throughout this pamphlet he confiders it as the work of Dr. Forfter, or as containing both the language and fentiments' of the father, though published in the name of the fon, for reajons of convenience. Thefe reafons may be found in the first pages of our critique above referred to; where, however, we declined difcuffing the cafuiftical merits of the proceeding. Mr. Wales, it will naturally be fuppofed, is not fo delicate. K 4 pro |