i84 



RESEARCHES UPON ATOMIC WEIGHTS. 



RATIO OF SILVER BROMIDE TO SILVER PHOSPHATE. 



The following table contains all of the analyses not vitiated by a known im- 

 purity in the sample or by an accident during the analysis. One feature of tliis 

 table requires further explanation. In analysis 5 the silver was determined by 

 precipitation as chloride instead of bromide. For every gram of silver phos- 

 phate there was obtained 1.02727 gm. of silver chloride. Since Baxter found 

 AgBr:AgCl= 1.31017:1.00000, this analysis indicates that one gram of 

 sample N is eciuivalent to 1.02704 X 1.31017 = 1.34560 gm. of silver bromide. 

 This result is placed in the table for comparison with the other analyses and is 

 used in the computation of the mean. 



Series I. 3 AgBr: AgsPO^. 



DISCUSSION OF RESULTS. 



A careful study of these results shows that the composition of silver phosphate 

 is very nearly, if not quite, independent of the changes in the acidity of the solu- 

 tions from which it is precipitated. Samples O and R were prepared under 

 slightly more acid conditions than Samiples N and P. The average amount of 

 silver bromide obtained from one gram of Samples and R is 1.34558 (77.297 

 per cent of silver), whereas the average from Samples N and P is 1.34564 

 (77.301 percent of silver). This difference, if real and significant, is probably 

 due to a very slight occlusion of disilver hydrogen phosphate. It does not seem 

 probable that any basic salt was present in Samples N and P, because silver 

 shows little tendency to form basic salts and the conditions of precipitation 

 were not favorable for the formation of basic salts. 



The difference between composition of the samples is so slight, both in abso- 

 lute amount and by comparison with the differences between different analyses 

 of the same sample, that in the present state of our knowledge it does not 



^ Loc. cit. 



