LECTURE VI.] HISTORY OF CHEMISTRY. 107 



f 



which latter, on account of its completeness, had, at that time, 

 already become widely distributed. 



With Gmelin, there is no strict distinction between mixtures 

 and compounds, and this proves that he does not believe in 

 the real existence of atoms. Two substances, especially when 

 they possess only a weak affinity for each other, can combine, 

 according to him, in an infinite number of proportions ; but 

 the greater the affinity, the greater is their tendency to combine 

 in few proportions only. 57 These proportions then stand to 

 each other in simple relations. "There can therefore be 

 assigned to every substance a certain weight in which it 

 combines with definite weights of other elements. This weight 

 is the stochiometric number, the chemical equivalent, the 

 mixture-weight or atomic weight, and so on. Compounds are 

 composed in such proportions that one mixture-weight of one 

 substance is united to J, \, \, f, }, i, i, 2, 2 J, 3, 4, 5, 6, 7, or 

 more mixture-weights of the other." According to Gmelin, 

 Gay-Lussac's law runs : One measure of an elastic fluid 

 substance combines with i, ij, 2, 2^, 3, 3^, and 4 measures 

 of the other. 



His table of equivalents is well known. It ran: H=i, 

 O = 8, S=i6, C = 6, etc. Water was written HO, and in 

 formulae generally, the endeavour was made to replace by 

 simplicity what they had lost in conception and in purpose. 

 Chemistry was to become a science confined to observation 

 indeed almost to description alone. Skill in manipulation was 

 all that was required ; speculation was banished as dangerous. 



It had come to this then : Inorganic chemistry, in connec- 

 tion with physics, had not been able to maintain the conception 

 of the atom. It is my business to show, in the next lectures, 

 how it was reintroduced into the science by means of organic 

 chemistry. 



57 Handbuch der theoretischen Chemie. Second Edition, 1821. 



