MINUTE CHEMICAL ERRORS. 



49 



The weight of the product, here CO2, divided by the 

 material used, here the diamond carbon, C, each one 

 determined by actual weighing, gives us the analytical ratio, 

 here n to 3 with almost mathematical exactness, as we shall 

 show in a subsequent chapter from the record; also p. 39. 



In this process of almost ideal perfection we have one 

 type of excellent atomic weight determination. 



As result hereof we find oxygen 16, exactly, as we shall 

 show. Thus practically, we have in C=i2 as diamond 

 standard of matter also found the old Berzelian Oxygen 

 Standard at 16 exactly. 



Oxidation of Metals. 



Some metals can be chemically produced in an almo.st 

 absolutely pure state, permanent in dry air, hence accurately 

 weighable. 



Some of these metals can, at a moderate degree of heat, 

 be completely converted into a definite, fixed oxide, which 

 therefore is also exactly weighable. 



Hence such metals are suitable for very accurate atomic 

 weight determinations by such a process of oxidation. 



Some of these metals, such as tin, may, by heating in a 

 current of hydrogen, again be reduced to the metallic state, 

 and thus permit a double determination of their atomic 

 weight. 



These methods of direct oxidation and reduction are among 

 the best, most direct and most accurate of all methods of 

 atomic weight determinations, and were used and perfected 

 by Berzelius and his disciples during the first quarter of the 

 nineteenth century. 



These standard methods of atomic weight determinations 

 we shall find to be infinitely more accurate than many of the 

 new methods. 



Dry Way Processes, and Crystals. 



In general, all dry way processes are infinitely preferable 

 to wet way processes. 



Erdmann and Marchand weighed the mercuric oxide and 

 distilled the mercury over by means of heat, collecting the 



