178 



PROPORTIONS DETERMINATE. 



which were likewise conformable to Dalton's hypo- 

 thesis. 



In their investigation concerning eudiometry, Messrs. 

 Hutnholdt and Gay Lussac had found, that the gasi- 

 Gf.iy Lus- form elements of water combine in such a proportion, 

 sac - that exactly two volumes of hydrogen are required to 



saturate one volume of oxygen. M. Gay Lussac, conti- 

 nuing 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 submultiple of. that volume. His memoir 

 on the mutual combination of gaseous substances is to 

 be found in the Memoires d'Arcueil, t. ii. 1809. These 

 experiments prove, in the most direct manner, that 

 Dalton's idea is just, if only the word volume be sub- 

 stituted for atom. M. Gay Lussac did not, however, 

 make any more general application of this precious dis- 

 covery. It had been said in the Stalique of Berthollet, 

 that gasiform substances must combine in fixed pro- 

 portions, 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 

 extensive application of which would doubtless have 

 widely changed M. Berthollet's manner of conceiving 

 the subject, in which Gay Lussac seems then to have 

 agreed with him. 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 elements ; and de- 

 noting the relative weight of the atoms, he had put 

 that of hydrogen the lightest, = 1 . If, 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 Arrangement 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, an 

 experienced reader will think he finds, even in com- 

 paring the results with those of Gay Lussac, new proofs 

 in favour of the laws established by the latter. At 

 present, the generality of chemists appear to admit 

 that Gay Lussac's observations agree with experience. 



Gay Lussac likewise examined the precipitation of 

 metals, in their metallic state, by other metals. The 

 results of his examination confirm what Bergman and 

 Richter had already advanced on this subject. 



But the most detailed and extensive course of ex- 

 periments concerning chemical proportions has been 

 performed by M. Berzelius of Stockholm. The works 

 of Richter had engaged this chemist to repeat the ex- 

 periments detailed in them, and correct their results. 

 He endeavoured to obtain data sufficiently exact 

 for enabling him to calculate, according to the rules 

 established by Richter, the composition of most saline 

 bodies. During this enterprise, the late analysis of the 

 alkalies induced him to give greater compass to his re- 

 searches, in order to determine the quantity of oxygen 

 contained in those bodies, and chiefly in ammonia, by 

 means of what Bergman, and still more what Richter 

 had discovered concerning the precipitation of metals 

 by each other. These experiments presented difficul- 

 ties at the very outset. Assuming as a groundwork 

 those analyses, M hich he had every reason to consider 

 as the best, he found them rather to contradict than 

 to confirm the laws already looked upon as proved. 

 But having studied to observe and avoid every circum- 



Berzelius. 



stance which might affect the result of an analysis, he 

 obtained at last a certain number of analytical results, 

 exact enough to correspond with the laws under con- 

 sideration. Of all the analyses performed before him, 

 none but those of Wenzel were found to coincide with 

 his own. The experiments of Dr. Wollaston, concern- 

 ing the multiple proportions of Dalton, having been 

 published in the Philosophical Transactions, (1808,) 

 M. Berzelius here entered upon a new field, deserving 

 more minute examination. The first series of M. Ber- 

 zelius' experiments was printed in a Swedish periodical 

 work, conducted by himself, along with M. Hisinger, 

 and entitled, Affandlingar i Fysik, Kemi och Minera- 

 logi. The various memoirs which he afterwards pub- 

 lished on this subject, are to be met with in the dif- 

 ferent journals of physics and chemistry ; such as 

 Dr. Thomson's Annals of Philosophy ; Mr. Nicholson's 

 Journal ; Mr. Tilloch's Philosophical Magazine ; the 

 Annales de Cf/ymie ; the Journal de Physique ; M. Gil- 

 bert's Annnlen dcr Physik ; M. Schweigger's Journal ; 

 no one of which, however, contains the complete col- 

 lection. It would be tedious in this place to exhibit 

 the entire series of his experiments on chemical pro- 

 portions ; it is enough to mention, that in order to ar- 

 rive i at the results, of which we are immediately to pre- 

 sent an exposition, he examined nearly all the oxides 

 having simple radicals ; many saline combinations, 

 among the greater part of acids and bases, having an 

 excess of base, or existing in a neutral state ; a multi- 

 tude of salts, with two bases, as well as salts with two 

 acids ; the chemical combinations of water with acids, 

 bases and salts ; some combinations of metals with 

 each other, and of metallic oxides with each other; he 

 extended his researches to minerals, of which he ana- 

 lyzed several himself, and examined the analyses made 

 of others by the most celebrated chemists of our age ; 

 and, finally, he likewise analyzed some vegetables. 

 The experiments of M. Berzelius differ from those of 

 the chemists already mentioned, in not having been 

 made to establish any preconceived hypothesis. On 

 the contrary, they form a course of study regarding 

 determinate proportions, from which the laws have 

 emerged by degrees, as the facts including them aug- 

 mented in number. From his experiments, M. Ber- 

 zelius concludes, that the laws, according to which 

 elementary substances combine, may, in so far as con- 

 cerns inorganic nature, be reduced to two principal 

 rules. First, when a body A combines with a body 

 B in several proportions, the numbers expressing those 

 proportions are integer multiples of the smallest quan- 

 tity of B that A can absorb ; so that if this quantity 

 of B were = 6, the other proportions must be some of 

 the following : 24*, 36, 48, &c. It is from this law that 

 Mr. Dalton's hypothesis acquires so much probability. 

 Secondly, when two oxidized bodies combine, the oxy- 

 gen of the one is an integer multiple of that contained 

 by the other ; or if the number of oxidized bodies is 

 greater, the oxygen of the body containing least is an 

 integer submultiple of the oxygen found in any of the 

 rest. In the sulphate of potass, for example, the oxy- 

 gen of the sulphuric acid is three times that of the 

 potass ; and in crystallized alum the oxygen contained 

 by the potass, which is the smallest quantity, is a sub- 

 multiple by three of that contained by the alumina, by 

 12 of that contained by the sulphuric acid, and by 24 

 of that contained by the water of crystallization. This 

 last rule, however, may be expressed in a more general 

 manner : Two compound bodies, the electro-negative 

 element of which is common, combine in such a ratio, 



6 



Propor- 

 tions, 

 Determi- 

 nate. 



