364 Report oF THE CHEMIST OF THE 
In studying the data embodied in Table II, we notice the 
following points of interest: 
(1) The total amount of sulphur in solution, as well as the 
amount of sulphur in sulphide form, tends to increase with the 
use of increased amounts of lime. 
(2) The amount of thiosulphate sulphur shows a tendency 
to be smaller when larger amounts of lime are used. We shall 
see later, in studying the composition of the sediment, that 
more sulphite sulphur is usually formed when increased 
amounts of lime are used. This indicates that more or less 
thiosulphate sulphur has been changed into sulphite sulphur 
and that in reality more thiosulphate has been formed than is 
indicated by the figures given in Table II. 
(3) The amount of calcium in combination in the form of 
soluble sulphides increases when the proportion of lime used 
increases. 
(4) The amount of sulphur for one part of calcium is least 
when the largest proportion of lime is used. Referring to the 
statements made on page 357, we have noticed that when a sul- 
phide of calcium is pure pentasulphide (CaS,), it contains 
four parts by weight of sulphur for one of calcium. When the 
ratio is lower, there is less calcium pentasulphide and more 
tetrasulphide (CaS,) and in some cases there is probably an 
admixture of soluble sulphides containing still less sulphur 
(CaS,, CaS,). Of course, the increase of calcium in solution 
may be accounted for to a small extent by the presence of 
calcium hydroxide (CaO,H,), which is present when an excess 
of lime is used. If the solubility of calcium hydroxide is no 
greater in the lime-sulphur wash than in water, the amount is 
practically negligible for our purposes. Referring to the last 
column in Table II, it is seen that when the smallest amount 
(52 pounds) of lime is used, the ratio of calcium to sulphur 
indicates in two experiments (1-a and 1-c) a calcium sulphide 
corresponding very closely in composition to the pentasulphide 
(CaS.). In experiment i-b, the ratio is about that required 
for the tetrasulphide (CaS,). Why the results of this experi- 
ment differ so markedly from the other two, we are not able 
