by Dr Thomas Young 437 



to be absorbed by an equal bulk of water or of olive-oil, and by less than half 

 its bulk of spirit of wine ; to exceed the atmospheric air in specific gravity by 

 more than one-half, and to render this fluid unfit for supporting combustion 

 even when added to it in the proportion of i to 9 only. Mr Cavendish ascer- 

 tained the quantity of this gas contained in marble and in the alkalis, but 

 his numbers fell somewhat short of those which have been determined by later 

 experiments ; he also observed the solubility of the supercarbonate of magnesia. 

 In the third part, the air produced by fermentation and putrefaction is examined. 

 Macbride had shown that a part of it was fixed air; and our author finds that 

 sugar and water, thrown into fermentation by yeast, emit this gas without 

 altering the. quantity or quality of the common air previously contained in the 

 vessel, which retains its power of exploding with hydrogen, exactly like common 

 air: he also shows that the gas thus emitted is identical with the fixed air 

 obtained from marble; and that the inflammable air, extricated during putre- 

 faction, resembles that which is procured from zinc, although it appeared to 

 be a little heavier. 



2. Experiments on Rathbone Place Water. (Phil. Trans. 1767, p. 92.) In 

 this paper Mr Cavendish shows the solubility of the supercarbonate of lime, 

 which is found in several waters about London, and is decomposed by the pro- 

 cess of boiling, the simple carbonate being deposited in the form of a crust: 

 the addition of pure lime-water also causes a precipitation of a greater quantity 

 of lime than it contains. These conclusions are confirmed by synthetical experi- 

 ments, in which the supercarbonate is formed and remains in solution. 



3. An Attempt to explain some of the principal Phenomena of Electricity by 

 means of an Elastic Fluid. (Phil. Trans. 1771, p. 584.) Our author's theory 

 of electricity agrees with that which had been published a few years before 

 by ^Epinus, but he has entered more minutely into the details of calculation, 

 showing the manner in which the supposed fluid must be distributed in a variety 

 of cases, and explaining the phenomena of electrified and charged substances 

 as they are actually observed. There is some degree of unnecessary complica- 

 tion from the great generality of the determinations: the law of electric 

 attraction and repulsion not having been at that time fully ascertained, 

 although Mr Cavendish inclines to the true supposition, of forces varying 

 inversely as the square of the distance: this deficiency he proposes to supply 

 by future experiments, and leaves it to more skilful mathematicians to render 

 some other parts of the theory still more complete. He probably found that 

 the necessity of the experiments, which he intended to pursue, was afterwards 

 superseded by those of Lord Stanhope and M. Coulomb; but he had carried 

 the mathematical investigation somewhat further at a later period of his life, 

 though he did not publish his papers * : an omission, however, which is the less 

 to be regretted, as M. Poisson, assisted by all the improvements of modern 



* It is generally understood that Sir William Snow Harris, the eminent electrician, 

 is engaged in the publication of these important papers. Note by the Editor [Dean 

 Peacock, in Young's Miscellaneous Works, vol. n, 1855. As regards the text, see 

 Maxwell's Introduction to this volume: also footnote, p. 433.] 



