SILVEE, POTASSIUM, ETC. 17 



and then in a stream of air. The sixth synthesis was simi- 

 lar to these, only the nitric solution was precipitated by 

 hydrochloric acid in slight excess, and the chloride thrown 

 down was washed by repeated decantation. All the de- 

 canted liquids were afterwards evaporated to dryness, and 

 the trace of chloride thus recovered was estimated in addi- 

 tion to the main mass. The latter was fused in an atmos- 

 phere of HCl. The seventh experiment was like the sixth, 

 only ammonium chloride was used instead of hydrochloric 

 acid. From 98.3 to 399.7 grammes of silver were used in 

 each experiment, the operations were performed chiefly in 

 the dark, and all weighings were reduced to vacuum. In 

 every case the chloride obtained was beautifully white. 

 The following are the results in chloride for 100 of silver : 



132.841 

 132.843 



132.843 

 132.849 

 132.846 

 132.848 

 122.8417 



Mean, 132.8445, =b .oooS 



We may now combine the means of these seven series, 

 representing in all thirty-three experiments. One hundred 

 parts of silver are equivalent to chlorine, as follows : 



Berzelius 32.757, dr .0190 



Turner 32.832, ±.0038 



Penny 32.8363, i .0012 



Marignac 32.839, it .0024 



Maumen6 32.7364, zh .0077 



Dumas 32.8755, dr .0044 



Stas 32.8445,^.0008 • 



General mean 32.8418, ± .0006 



Here, again, we have a fine example of the evident com- 

 pensation of errors among different series of experiments. 

 We have also another tribute to the accuracy of Stas, since 

 this general mean varies from the mean of his results only 

 within the limits of his own variations. 



