COMPOSITION" OP LIME-SULPHUR ANIMAL DIPS. 11 
the reaction between lime and sulphur. To the writer it appears 
logical to believe that in a boiling solution containing both lime and 
sulphur, that is, an unfinished solution like Preparation Q, there is 
little but pentasulphid present. If any lower polysulphid really is 
the first product, it apparently at once takes up more sulphur and 
becomes pentasulphid. Especially is this likely to be true from the 
well-known fact that hot solutions can dissolve notably more sulphur 
than corresponds to the formula CaS 5 . If the foregoing is granted, 
then it follows, that tetrasulphid present at the end has mainly re- 
sulted from the secondary reaction of pentasulphid with lime. 
HIGHER POLYSULPHIDS; EFFECT OF OXIDATION. 
When a lime-sulphur solution is exposed to air, calcium polysul- 
phid is oxidized to calcium thiosulphate and sulphur. It seems ra- 
tional that in the presence of this nascent sulphur calcium polysul- 
phid remaining undecomposed should pass to the highest possible 
stage of sulphurization, and that data thus obtained regarding the 
highest polysulphid of calcium existing in solution should be much 
more trustworthy than those derived from the rather dubious method 
of Auld 8 which led him to infer the existence of polysulphids much 
higher than the pentasulphid. 
EXPERIMENT 11. 
A portion of a dilution prepared about two months previously from a con- 
centrate of high lime-sulphur ratio was vigorously shaken in a flask connected 
without exit tube with a small gasometer of pure oxygen. A considerable 
quantity of oxygen was absorbed while the solution remained perfectly clear, 
during which stage the nascent sulphur was evidently wholly entering combi- 
nation to produce higher calcium polysulphids than were originally present. 
At a certain point, however, the solution suddenly became opalescent, and 
thereafter rapidly increased in turbidity. Treatment with oxygen, which 
altogether occupied but a brief time, was stopped when a considerable quantity 
of free sulphur appeared present, and the solution was transferred to a well- 
filled and sealed bottle. Vigorous shaking coagulated the sulphur, but some 
air had become entangled, so it was necessary the next day to filter rapidly 
through a loose plug of cotton, after which both the original solution (sample 
R-l) and the oxidized solution (sample R-2) were analyzed. The titration 
results are given in Table 1. 
The value of x in the M 2 S X of sample R-l was, therefore, 4.44, 
while after oxidation the value of x in CaS x for sample R-2 rose to 
4.99. Another experiment in which a very slow current of air was 
bubbled for a long time gave exactly the same figure. Therefore it is 
plain that a lime-sulphur solution as applied in practice never con- 
tains a calcium potysulphid higher than the pentasulphid. On the 
other hand any lower polysulphid present in the solution before appli- 
cation probably becomes pentasulphid through free contact with air 
soon after if not during the process of application. 
