Yet, upon repeating those experiments, with all possible care as it would seem, M. do Saussure has just found that Mr. Dalton's results are without foundation ; and that not only different liquids absorb different quantities of the same gas, but that even the same liquid, mixed with a substance soluble in it, loses much of its absorbent power. Nor has the ratio which, according to Mr. Dalton, the volume of the absorbed gas bears to that of the absorbent liquid, been better confirmed by the experiments of De Saussure. The following is a comparison between some of their results.
100 measures of water absorb of (According to Saussure.) (According to Dalton.) Carbonic acid gas, - 106 - 100 = 1 Volume.
Sulphurated hydrogen gas, 253 - 100 = 1 Nitrous oxyd gas, 76 - 100 = 1 Olefiant gas, - 15.5 - 12.5 • = 7 Oxygen gas, 6.5 - 3.7 = Nitrogen gas, 4.0 - 1.56 = These differences serve to show how science may be injured, when the cultivator of it is one who, with little accuracy in experimenting, possesses great confidence in his own labours, and enough of sagacity to diffuse a mathematical plausibility over his results. It is much to be feared, that, notwithstanding the new information which we owe to the doctrine of chemical proportions, the abuse made of that principle by unscrupulous chemists may occasion very considerable mistakes.
Mr. Dalton's opinions at first excited little interest; but some experiments of Dr. Wollaston awakened the atten tion of chemists. It is a necessary consequence from the atomic system of Mr. Dalton, that if A can combine with B in more than one proportion, the latter must be 2, 3, Ecc. times B. Wollaston weighed a portion of the superoxalate of potass, and expelled its acid by fire. The potass that remained, when added to a portion of the superoxalate, equal to that which had just been burned, rendered it exactly neutral. Another portion of the superoxalate being dissolved in diluted muriatic acid, and evaporated to crystallization, produced a superoxalate with a greater excess of acid. Having roasted a certain quantity of it, he now observes how much of the same salt not burned was required to neutralize the potass obtained ; three parts el the burned potass were required to saturate one part of the unburned maximum superoxalate. From these ex periments, no less simple than ingenious, it follows that potass combines with three portions of oxalic acid, bearing to one another the ratio of 1, 2, and 4. Wollaston sub
joined some other experiments, the results of which were likewise conformable to Dalton's hypothesis.
In their investigation concerning eudiometry, Messrs. Humboldt and Gay Lussac had found, that the gasiform elements of water combine in such a proportion, that exactly two volumes of hydrogen are required to saturate one volume of oxygen. M. Gay Lussac, continuing his researches, discovered that gases in general combine in such a manner as to have a volume of the one united either to a volume of the other, or to some multiple or subrnuI tiple of that volume. His memoir on the mutual combi nation of gaseous substances is to be found in the Memoires d' Arcueil, t. ii. 1809. These experiments prove, in the most direct manlier, that Dalton's idea is just, if only the word volume be substituted for atom. 1\1. Gay Lussac did not, however, make any more general application of this precious discovery. It had been said in the Statique of Berthollet, that gasiform substances must combine infixed proportions, because they suffer a great condensation in that process; and M. Gay Lussac contented himself with having found the law of these proportions—a more ex tensive application of which would doubtless have widely changed Al. Berthollet's manner of conceiving the subject, in which Gay Lussac seems then to have agreed with hint. Mr. Dalton, instead of hailing the triumph offered him by this discovery, struggled, on the contrary, to dispute its correctness. He had grounded his calculations on the idea that water is formed by one atom of each of its ele ments; and denoting the relative weight of the atoms, he had put that of hydrogen the lightest, = 1. lf, on the other hand, M. Gay Lussac's opinion was just, it seemed much more natural to regard water as containing two atoms of hydrogen. Mr. Dalton drew Profile Views of the Disposition and ?rrangement of Particles constituting Elastic Fluids, both Simple and Compound ; and, finally, combined some experiments to prove, that two gases are never condensed in the proportions assigned by M. Gay Lussac. Yet in perusing Mr. Dalton's work, experi enced reader will think he finds, even in comparing the results with those of Gay Lussac, new proofs in favour of the laws established by the latter. At present, the gene rality of chemists appear to admit that Gay Lussac's ob rervations agree with experience.