c. of the nickel solution, equal to .0445 gram of nickel.
There were also 10 c.c. of soda solution, 3 or 4 drops of potassium
iodide and sufficient water to bring the bulk to 100 c.c. before
titrating.
Cyanide in excess 6 c.c. 4 c.c. 8 c.c. 12 c.c. 25 c.c.
Nickel found .0434 .0436 .0440 .0442 .0444
Although the difference between the highest and lowest of these results
is only 1 milligram, their meaning is quite obvious. The excess of
cyanide should not be less than 20 c.c.
~Effect of varying the quantity of Soda.~--There were two series of
experiments, one with 2 c.c. of nickel solution (= .0044 gram of
nickel), the other with 20 c.c. The conditions were as before, except
that the quantity of soda was varied.
Soda added 5 c.c. 15 c.c. 30 c.c.
Nickel found, 1st series .0037 .0042 .0045
" " 2nd series .0444 .0444 .0442
These show that the presence of much soda, though it has only a small
effect, is beneficial rather than otherwise. Ammonia has a bad effect,
if present in anything like the same quantities.
~Effect of varying the Nickel.~--In experiments with 10, 20, and 40 c.c.
of the nickel solution, the results were:--
Nickel present .0222 .0445 .0890
Nickel found .0220 .0442 .0884
~Effect of Zinc.
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