742 
Proceedings of the Royal Society of Edinburgh. [Sess. 
Table IV. — Ratios obtained from the Analysis of Potassium Chloroplatinate. 
Comparison of Silver with Platinum and with Potassium Chloroplatinate. 
Experi- 
ment. 
Parts 
of Pt = 
100-00 
parts of 
4Ag. 
Atomic 
Weight 
of Pla- 
tinum. 
Parts 
of Pt = 
100-00 
parts of 
2Ag. 
Atomic 
Weight 
of Pla- 
tinum. 
Parts of 
K„PtCL 
= 100-00 
parts of 
4Ag. 
Atomic 
Weight 
of Pla- 
tinum. 
Parts of 
KoPtCL 
= 100-00 
parts of 
2Ag. 
Atomic 
Weight 
of Pla- 
tinum. 
1 
45-238 
195-21 
90-498 
195-25 
112'65 
195T5 
225-36 
195-27 
2 
45-233 
195-19 
90-484 
195-23 
112-65 
195T4 
225-35 
195-24 
3 
45-235 
195-20 
90-498 
195-26 
112-65 
195-13 
225-37 
195-28 
4 
45-251 
195-27 
90-478 
195-22 
112-68 
195-28 
225-31 
195-16 
5 
... 
... 
90-510 
195-29 
... 
... 
225-36 
195*27 
6 
45-234 
195-20 
90-480 
195-22 
112-65 
195-15 
225-33 
195-20 
8 
45-227 
195-16 
90-460 
195*18 
112-65 
195-13 
225-31 
195-17 
9 
45-244 
195-24 
90-499 
195-26 
112-65 
195T6 
225-33 
195-21 
10 
45-240 
195-22 
90-488 
195-24 
112-68 
195-19 
225-37 
195-29 
11 
45-236 
195-20 
90-463 
195-18 
112-66 
195-19 
225-30 
195-14 
12 
45-252 
195-27 
90-487 
195-24 
112-68 
195-25 
225-31 
195-16 
18 
45-251 
195-25 
90-486 
195-23 
112-70 
195-29 
225-35 
195-25 
24 
45-237 
195-21 
90-484 
195-23 
112-67 
195-21 
225-36 
195-26 
Average 
45-240 
195-22 
90-486 
195*23 
112-66 
195-19 
225-34 
195-22 
It appears from the foregoing results that the different methods 
adopted for the purification of the platinum salt have yielded pro- 
ducts of a considerable degree of purity, or else some particular im- 
purity is present to the same extent in each sample — a rather unlikely 
supposition. The different samples are probably not all equally pure, 
but the amount of impurity is not large enough to affect the value for 
the atomic weight beyond what may be regarded as the experimental 
error. This would seem to be true as well for the different preparations 
of silver. 
If we compare the values obtained for different ratios, it does not appear 
that any particular ratio gives consistently a higher or a lower value than 
any other, and this seems to be the best argument for the purity of the 
salt and the exactness of the analysis. If, for instance, potassium chloride 
was occluded in appreciable amounts during precipitation, the ratio 
2AgCl : Pt would always give a low result, or if PtCl 4 was occluded, a high 
result would be obtained. Again, if water still remained in the salt after 
heating to 380°, the ratio K 2 PtCl 6 : Pt would give a low value for the atomic 
weight. If some of the chlorine had been replaced by hydroxyl, this 
ratio would give a high value while the ratio 4AgCl : Pt would be still 
higher. On the other hand, if, during the analysis, the potassium chloride 
had not all been washed out of the platinum, the ratio 2AgCl : Pt would 
