OP ARTS AND SCIENCES. 31 



able agreement between these results and the mean of the first five is 

 in itself a proof that we have been successful, and, moreover, their close 

 agreement among themselves indicates that, so far as the mere mechani- 

 cal details of the process are concerned, a perfection has been reached 

 which will compare favorably vv^ith the most accurate methods of quan- 

 titative analysis. In order to exhibit the details of the work as far as 

 practicable, we give below two examples of the most trustworthy deter- 

 minations. The first is selected from the group 8-12, and is one in 

 which no account is taken of the occluded material, but where it is be- 

 lieved that the conditions were so regulated that the two chief sources 

 of error must on the average (not, however, necessarily in every deter- 

 mination) balance each other. This example is selected, because, al- 

 though no account was taken of the carbonaceous residue, it was deter- 

 mined and examined, and thus some data are given for judging not 

 only how large the errors were, but also how nearly they were 

 balanced. The second example is unique. In this case, by a for- 

 tuitous concurrence of conditions, there was no oxichloride formed 

 even in a solution containing an excess of hydrochloric acid, and 

 no material sublimation of any antimony product. Here, then, we 

 have fortunately a determination belonging to the same class as the 

 others, in which the error is known to be all on one side, and w'here 

 the error can be corrected by determining the carbonaceous residue. 

 Since, moreover, in the details of its execution, this determination was 

 faultless in every respect, the result it furnishes is of very great value 

 as a standard of comparison. And, further, since the tendency of 

 every known error not corrected by subtracting the carbonaceous 

 residue is in the opposite direction, it seems impossible, at least, with 

 our present knowledge, that the atomic weight of antimony should be 

 greater than the value thus obtained. 



Details of Determination marked No. HE. 



The finely pulverized antimony was weighed in a platinum nacelle. 

 By means of a loop of platinum wire, this nacelle was lowered into 

 a glass flask having a capacity of about 150 cubic centimetres. The 

 powder having been shaken out, the nacelle was withdrawn, replaced 

 on the balance pan, and weighed. 



Weight of nacelle and antimony . . . 8.2655 grammes. 

 « „ 6.2617 



"Weight of antimony transferred to flask . 2.0038 



