308 Chittenden and W hitehouse—Metallic 
Srriges VII. 
With CuSO,. 
No. Am’t sub. taken. Wt. CuO. Per cent. Cu. Wt. Cus. Per cent. Cu. 
la 0°6326 gram. 0:0091 gram. 1:13 =e ttt 
b 06156 0-0086 1°10 pe ies 
2a 04054 0-0081 1:60 0:0063 gram. 1°23 
b 0°4995 00099 1°58 0-0074 1-19 
3a 0:3870 0-0068 1:39 00049 1-02 
b 03702 00066 1:40 
With Cu(C,H,0,),. 
4a 06175 00085 1:08 00074 0°95 
b 06069 0)-0082 1:07 0-0077 1:00 
5a 0°3282 00072 1°73 00055 1°34 
b 0°3755 0-0088 1°75 Eee ose 
6a 0°7508 00132 1°39 00104 1:10 
b 0°7016 0°0121 1°38 
This series was prepared in the same manner as the preceding. 
Nos. 1,3, 4 and 6 were simply washed with water, while No. 2 was 
reprecipitated once and No. 5 twice, and both ultimately washed free 
from all soluble matters. The results show here the same increased 
percentage of copper, although not so marked as in the preceding 
series, when the albuminate is dissolved in sodium carbonate and 
reprecipitatéd. Further, the percentage of ash is not, as a rule, 
materially changed by this process; thus in No. 2, where the albu- 
minate was reprecipitated once, the difference in the percentage of 
copper as determined by simple ignition and by precipitation as 
sulphide, amounts to 0°37 per cent., while in No. 3a, where the 
compound was not reprecipited at all, the difference is exactly the 
same. 
In precipitating the albuminate, there is formed in the fluid a 
small amount of either sulphuric or acetic acid. Harnack, to avoid 
this, states that it is better, after adding the necessary amount of cupric 
sulphate to the albumin solution, to exactly neutralize the mixture with 
sodium carbonate. If, however, the greatest care is not exercised and 
excess of cupric sulphate avoided, even partial neutralization of the fluid 
will result in the precipitation of a portion of the copper and thus 
show an apparent increase in the copper of the albuminate. So far, 
however, as our results show, the small amount of sulphuric acid libera- 
ted in the formation of the albuminate does not affect the character 
of the compound. In the following series, after each precipitation, 
