1815.] in the Physical Sciences. \\ 



considtred himself as entitled, by the results which he has obtained, 

 to establish two propositions which he considers as axioms or che- 

 mical first principles, and which liave a prodigious influence on the 

 whole doctrine. These axioms arc the following : — 



1 . in all com])ounds of inoi-ganic matter one of the constituents 

 is always in the state of a single atom. According to this axiom, 

 no inorganic compound is ever composed of two atoms of a united 

 with three atoms of h^ or of three atoms of a united with four atoms 

 of /', &c. ; but always of one atom of a united with one, two, 

 three, four, &c. atoms of b. This axiom, if it hold good, which 

 Berzelius thinks it will, greatly simpHfies the doctrine of atomic 

 conjbination, as far as inorganic bodies are concerned, and reduces 

 the whole to a state of elementary facility. 



2. When an acid unites to a base, the oxygen in the acid is 

 always a multiple of the oxygen in the base by a whole number, 

 and generally by the number denoting the atoms of oxygen in the 

 acid. Thus sulphuric acid contains three atoms of oxygen : 100 

 parts of it contain GO oxygen ; and 100 parts of sulphuric acid 

 combine with, and saturate, a quantity of base which contains 20 

 oxygen. Now 20 multiplied by three, the number of atoms of 

 oxygen in sulphuric acid, makes 60 the quantity of oxygen in 100 

 of sulphuric acid. 



Such are the two axioms of Berzelius, which he has made the 

 foundation of his whole reasoning, and from which he has deduced 

 his rules for determining the proportion of oxygen in bodies, and 

 the number of atoms of which they are composed. If they hold 

 good, and hi'.lierto they have answered wonderfully well, they nius^ 

 be admitted to be of the utmost importance, and to give a facility 

 and elegance to our chemical investigations which could scarcely 

 have been looked for. 



Mr. Dalton, the founder of the atomic theory, has not adopted 

 either of these axioms. Ai the same time he has not advaoced any 

 fact in opposition to them ; but only that there is nothing in the 

 atomic theory which necessarily leads to their adoption. This is 

 doubtless true. The axioms arc merely empyrical, and deductions 

 from analy'>es. Yet if they hold in all the analyses hitherto made, 

 we caimot well refuse them a good deal of generality ; and the 

 be.-t mode of proceeding seems to be to admit tlieia till some 

 exception to them be discovered. 



Berzelius, considering the atomic theory to labour under diflicul- 

 tie?, wliicli in the present slate of our knowledge we are not able 

 to surmount, has substituted in its place another, which he con- 

 ceives to b<.' easier and sim])k'r. This may be called tlie theory of 

 volumes. He conceives bodies to be all in the gaseous state, and 

 embraces the opinion of (Jay-LAissac, that gaseous bodies always 

 unite in voliuiKs that are alicjuot parts of each other. One volume 

 'A one body always unites with one, two, three, &c. volumes of 

 annihcr. How ttiis alteration, which consists merely in the substi- 

 tution of the word volume for atom, simplifies the atomic theory, of 



