LECTURE VI.] HISTORY OF CHEMISTRY. QI 



With these indications, we shall now leave this matter, and 

 pass on to a much more important subject in the system of 

 Berzelius, that is, to the mode by which he determined the 

 number of atoms in a compound. He was the first who took 

 account of purely chemical facts in these determinations. He 

 rejects Dalton's rules entirely, pointing out, with justice, their 

 groundlessness : " When only one compound is known, there 

 is surely something arbitrary in assuming that it consists of 

 one atom of each element, altogether regardless of the other 

 relations of the compound." 14 



Berzelius tries to establish the view, however, that regu- 

 larities must exist, which determine the number of the atoms 

 that mutually combine with one another. 15 He argues that if 

 an unlimited number of atoms of one element could combine 

 with an unlimited number of atoms of another, there would, in 

 this way, be produced an infinite number of compounds which 

 would differ so little in composition that even our best analyses 

 would fail to show any difference. The view that substances 

 consist of indivisible atoms, and that chemical compounds are 

 produced by the arrangement of these atoms side by side, is 

 not sufficient to explain multiple proportions. In the combina- 

 tion of atoms, special laws must prevail which limit the number 

 of the compounds ; and it is upon these laws, in particular, 

 that chemical proportions depend. 



He finds his first basis in Gay-Lussac's law of gaseous 

 volumes. 



This law appears to him to permit of an unequivocal 

 decision of the question, since, with him, atom and volume are 

 identical in the case of simple gases. " We know, for example, 

 with certainty the relative number of atoms of nitrogen and of 

 oxygen in the different stages of oxidation of nitrogen ; that of 

 nitrogen and of hydrogen in ammonia; that of chlorine and 

 oxygen in the different stages of oxidation of chlorine ; " 16 and 

 so on. Amongst the gases, the law of multiple proportions 



14 Lehrbuch. 3, part I, 88. 15 Essai etc. 28. 16 Lehrbuch. 3, 



part I, 89. 



