42 THE ATOMIC WEIGHTS. 



Marignac's* results were as follows. In the third column 

 they are reduced to the common standard of 100 parts of 

 silver : 



68.987 grm. Ag gave 108.608 grm. AgNOj. 157-433 



57.844 " 91-047 " 157-401 



66.436 " 104.592 « 157-433 



70.340 " 1 10.718 " 157.404 



200.000 " 314-894 " 157-447 



Mean, 157.4236, dz .0061 



StaSjf employing from 77 to 405 grammes of silver in 

 each experiment, made two different series of determina- 

 tions at two different times. The silver was dissolved with 

 all the usual precautions against loss and against impurity, 

 and the resulting nitrate was weighed, first after long drjdng 

 without fusion just below its melting point; and again, 

 fused. Between the fused and the unfused salt there was in 

 every case a slight difference in weight, the latter giving a 

 maximum and the former a minimum value. 



In Stas' first series there are eight experiments ; but the 

 seventh he himself rejects as inexact. The values obtained 

 for the nitrate from 100 parts of silver are given below in two 

 columns, representing the two conditions in which the salt 

 was weighed. The general mean given at the end I have 

 deduced from the means of the two columns considered sep- 

 arately : 



IMfuscd. Fused. 



157-492 157-474 



157-510 157-481 



157-485 157-477 



157-476 157-471 



157.478 157-470 



157.471 157-463 



157.488 157-469 



Mean, 157.4857 Mean, 157.472 



General mean, 157.474, dz .0014 



* Berzelius' Lehrbuch, 5th Ed., 3, pp. 1184, 1185. 

 f Aronstein's Translation, pp. 305 and 315. 



