316 



THE ATOMIC WEIGHTS. 



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

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

 he abandoned its use, and resorted to palladiammonium chloride, 

 Pd(NH 3 Cl) 2 , as the most available compound for his purpose. 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 : 



Pd(NH,Cl},. 

 .83260 

 .72635 

 .40280 

 57940 

 .89895 

 .48065 



56015 



.82658 

 2.40125 

 1.10400 



933 10 



First Series. 

 Pd. 



41965 

 .86992 

 .70670 

 .79562 

 .95650 

 74570 

 .78585 

 .92003 

 1.20970 

 .55629 

 .47010 



Percent. Pd. 

 50.402 



50-391 

 50.378 

 50.375 

 50.370 

 50-363 

 50.370 

 50-369 

 50.378 

 50.389 

 50.380 



Reduced to vacuum this becomes 50.360, 



Second Series. 



Pd. 



1.31900 

 1.12561 



.87445 

 .85210 

 .86825 



.56535 



.59200 



1.22280 



2.61841 

 2.23420 



73553 

 .69160 

 .72403 



.12222 



17457 

 2.42760 



Mean, 50.379, .0008 



Per cent. Pd. 



50.374 

 50-381 

 50.385 

 50.372 

 50.362 

 50.378 

 50.401 

 50-37I 



Mean, 50.378, 

 Reduced to vacuum, 50.359 



.0028 



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. 



*Am. Chem. Journ., n, 398. 1889. 

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



