316 THE ATOMIC WEIGHTS. 



In 1889 Keiser's first determinations of this constant appeared.* Find- 

 ing the potassium palladiochloride to contain " water of decrepitation," 

 he abandoned its use, and resorted to palladiammoniura chloride, 

 PfKNHaCl).,, as the most available compound for his ])urpose. This 

 salt, heated in hydrogen, yields spongy palladium, which was allowed 

 to cool in a current of dry air, in order to avoid gaseous occlusions. The 

 salt itself was dried, previous to analysis, first over sulphuric acid, and 

 then in an air bath at a temperature from 120° to 130°. Two series of 

 experiments were made, the second series starting out from palladium 

 produced by the first series. The data are as follows : 



First Series. 



Pd{NH.,a\. Pd. Per cent. Pd. 



.83260 .41965 50.402 



1-72635 .86992 50.391 



1.40280 .70670 50.37S 



1.57940 .79562 50.375 



1.89895 .95650 50.370 



1.48065 .74570 50.363 



1. 56015 .7S585 50.370 



1.82658 .92003 50.369 



2.40125 1.20970 50.378 



1. 10400 .55629 50.389 



.933'o .47010 50.380 



.0008 



Mean, 50.37S, d= .0028 

 Reduced to vacuum, 50.359 



The reductions to vacuum are neglected by Keiser himself, but are here 

 added in order to secure uniformity with later results by the same author. 

 The mean of both series, thus corrected, gives Pd = 105.74. 



Bailey and Lamb f made experiments upon several compounds of pal- 

 ladium, but finally settled upon palladiammonium chloride, like Keiser. 



*Atn. Chem. Journ., ii. 398. 1889. 

 t Journ. Chem. Soc, 61, 745. 1892. 



