330 THE ATOMIC WEIGHTS. 



PL *AgCL Ratio. 



6.7771 2.7158 7.9725 85.006 



3.5834 L4372 4.2270 84.774 



4.4139 1.7713 5-2144 84.648 



Mean, 84.809, .071 



Halberstadt,* like Seubert, studied the chloroplatinates of potassium 

 and ammonium, and also the corresponding double bromides and platinic 

 bromide as well. The metal was estimated partly by reduction in hy- 

 drogen, as usual, and partly by electrolysis. Platinic bromide gave the 

 following results : 



I. By Reduction in H. 



PtBr^. Pt. Per cent. Pt. 



.6396 .2422 37.867 



1.7596 .6659 37.844 



.9178 .3476 37.873 



1.1594 .4388 37.847 



1.9608 .7420 37.842 



2.0865 .7898 37.853 



4.0796 1.5422 37-852 



6.8673 2.5985 37-8j9 



77. By Electrolysis. 



1.2588 .4763 37-837 



1-4937 .5649 37-819 



Mean of all ten experiments, 37.847, .0033 



The ammonium platinbromide, (NH 4 ) 2 PtBr 6 , was prepared in two 

 ways, and five distinct lots were studied. With this salt, as well as with 

 those which follow, the data are given in distinct series, with from one 

 to several experiments in each group, but for present purposes it seems 

 best to consolidate the material and so put it in more manageable form. 

 The percentages of platinum and weights found are as follows : 



/. By Reduction in H. 



Pt. Percent. Pt. 



*Ber. Deutsch. Chem. Gesell., 17, 2962. 1884. 



