1825.] M. Berzelins's Hypothesis of the Atomk Theory. 337 



Suppose we have found that a sulphuret of lead is com- 

 posed of 



Lead 86 



Sulphur 14 



Too 



Here a certain number of atoms of lead, whose total weight is 

 ^Q, were combined with a certain number of atoms of sulphur, 

 whose weight is 14. If, therefore, we divide 86 by the number 

 representing the weight of the atom of lead (which we find in 

 the tables is 104), and 14 by that of the atom of sulphur, (16), 

 suppressing the decimal point in both cases, we find that the 

 compound contains 82 atoms of lead and 87 atoms of sulphur, 

 numbers which are very nearly equal. Hence we conclude that 

 the mineral is composed of 1 atom of lead and 1 atom of sulphur ; 

 and if we calculate the results which our analysis ought to give 

 on this supposition, we find the numbers to be 



Lead 86-66 



Sulphur 13-33 



which accord very nearly with the results of the experiment. 



A similar operation will enable us to find the atomic compo- 

 sition of all other binary compounds, whose analysis is known. 



Let us now take an instance of some more complex compounds, 

 and calculate them on the data and numbers assumed by Ber- 

 zehus.* 



Suppose an analysis of molybdate of lead (a ternary combina- 

 tion) had given, 



Oxide of lead 61 



Molybdic acid 39 



Too 



We find in the annexed table, that the quantity of oxygen in 

 oxide of lead is 7*171 per cent, and that in molybdic acid 33-45; 

 consequently 61 of the former contain 4-37 of oxygen, and 39 of 

 the latter 13-04; but 4-37 : 13-04 :: 1 : 3; or the oxygen of 

 tlie acid is three times that of the b-ase ; but we observe in the 

 tables that the base contains only 2 atoms of oxygen, whilst the 

 acid contains 3 ; therefore to preserve the ratio of 1 : 3, there 

 must be 2 atoms of acid to 1 of base. The results of the analysis 

 calculated on these data give 



Oxide of lead 60-86 



Molybdic acid 39-14 



100-00 



J • In which oxygen = l(K). The examples are taken from Bewdant, p. 225, et seq. 



Neiw Series, vol. ix. z 



