78 PROCEEDINGS OP THE AMERICAN ACADEMY. 



say that organic matter was carefully excluded during all the opera- 

 tions, but nevertheless the argentic chloride was not absolutely color- 

 less after fusion. Perhaps the trace of phenol phthalein and methyl 

 orange may have caused a slight decomposition. It will be seen how 

 the introduction of these indicators was avoided before the close of 

 the investigation. 



The final corrected weight of the argentic chloride was found as 

 follows : — 



Grams. 



Weight in air of AgCl in Gooch crucible = 8.7G657 



Correction to vacuum (T° = 22°, H = 76 cm.) = +0.00062 



Weight in vacuum of AgCl in Gooch crucible = 8.76719 



Loss on fusion in porcelain crucible = — 0.00050 



Weight of main mass of fused AgCl = 8.76669 



Weight of AgCl found in wash water = +0.00093 



Total argentic chloride = 8.76762 

 Corresponding to 0.26 c.c. standard HO added in titration = —0.00035 



Corrected weight of argentic chloride in vacuum = 8.76727 



Since it seemed hardly probable that either of the chlorides was in 

 this case weighed more accurately than within 0.1 milligram, the fifth 

 place of decimals is omitted below. This practice was always adhered 

 to unless the fifth place seemed to have some significance. 



Experiment 20 then leads us to conclude that the ratio of argentic 

 chloride to baric chloride is 8.7673 : 6.3697 = 100.000 : 72.653. 

 Hence, the atomic weight of barium is easily found to be 137.435, 

 a result which agrees almost exactly with that obtained from baric 

 bromide. 



The other analyses were conducted in a similar manner. In some 

 cases, where it was suspected that the wash water carried with it a 

 trace of finely divided asbestos, the whole quantity was filtered through 

 a washed filter, and the weight found, if appreciable at all, was added 

 to the weight of the Gooch crucible. The table given below is proba- 

 bly comprehensible without further remark, except perhaps the state- 

 ment that the two figures given in the third column represent the 

 corrections for the baric hydroxide and baric carbonate respectively. 



The weights in the following cases are reduced to the vacuum 

 standard. 



