38 THE ERRORS OF PRECISION. 



leagues, who in publications and in their rostrum made 

 practical use of my work. 



It is not for me to examine how it happens that these 

 leading chemists of France are foisting upon the chemical 

 public of the world, work crowned at their recommendation 

 by the famous Academy of Sciences of Paris, work that gives 

 new data notoriously and necessarily erroneous, because 

 these great chemists have not found time to intelligently 

 read the papers published in the Comptes Rendus of their 

 own academy. 



So far as Professor A. Gautier is concerned, he has 

 repeatedly acknowledged the value of my contributions to 

 the Comptes Rendus and the importance of my critical 

 examination of the work of Stas, which implies the falsity 

 of the value of 14.04 for nitrogen. 



Is this throwing away the labor of young French Chem- 

 ists and the production of new errors and false atomic 

 weights in any way connected with that old French Institu- 

 tion: Le Cumul? 



VIII. ERRORS OF WEIGHING. 



The last laboratory operation in a chemical determina- 

 tion of the atomic weight is the -weighing of the product 

 obtained. 



The first operation, after obtaining the pure material or 

 substance was likewise a weighing, namely the determination 

 of the exact amount of substance operated upon. 



These weighings may be reduced to vacuum. 



The weight s of the substance taken, and the weight/ of 

 the final product obtained, are the only data of the actual 

 experimental determination made. 



To express these results in a common unit, all experi- 

 ments are referred to the unit of weight, by dividing the 

 weight of the product by that of the substance used. 



The quotient thus obtained is the only true final expres- 

 sion of the experiment or determination made. We call 

 this quantity the analytical ratio. 



Every individual determination actually made is thus 



