2 BULLETIN 451, TJ. S. DEPARTMENT OF AGRICULTURE. 
parison of results. The lime used was prepared from chemically 
pure calcium oxid by slaking and drying out, then passing through 
an 80-mesh sieve. Its content in available calcium oxid was deter- 
mined by the phenol solution method of Lindet and Brasart. 3 The 
sulphur used was sifted U. S. P. flowers, assumed without analysis 
to be sufficiently pure for the purpose. 
The methods of analysis have been fully described in the previous 
papers referred to. For the sulphid-acid figure " Method B " was 
employed, while the sulphid-base figure was not directly determined, 
since it can be obtained with greater accuracy by algebraic addition 
of the sulphid-acid figure and the reaction figure. All determina- 
tions were performed in duplicate. 
EFFECT OF STORAGE. 
EXPERIMENT 1. 
The first series of experiments, as it happened, was directed toward a study 
of the stability of lime-sulphur solutions during storage. A number of prepara- 
tions made for another purpose had been partially analyzed when other matters 
interrupted. On resumption of the work it seemed best to repeat all the de- 
terminations previously executed. The results are given in Table 1, under 
Experiment 1. 
The formulas employed were based on 100 parts of sulphur in all cases, while 
the lime is expressed in proportional parts available calcium oxid. The pro- 
portional parts of water given include both water added as such and the water 
of hydration of the lime. The lime and sulphur were thoroughly mixed dry 
in the container in which the solution was to be prepared — a 500 c. c. Kjeldahl 
flask. The desired amount of water, usually 200 c. c, was then added gradu- 
ally with thorough mixing. The mixtures were brought to boiling under reflux 
in about five minutes, and only the period of actual boiling was counted. 
Shortly before the end of the boiling period, during which the flask was fre- 
quently shaken, a stream of illuminating gas washed through caustic-soda solu- 
tion was introduced through a narrow tube passing down the condenser into 
the neck of the flask. The flask was partially cooled under these conditions by 
immersion in water, then the well-mixed contents were transferred to 4-ounce 
iple oil" bottles, which were filled into the necks and sealed. When cold 
the bottles were thoroughly shaken to insure a uniform solution. 
The results of Experiment 1 show that within the range of prac- 
tice, no matter what the formula or conditions of preparation may 
have been, all lime-sulphur solutions stored after decantation from 
Lment will acquire a distinct negative reaction figure in course of 
time. Divers and Shimidzu 4 qualitatively showed the reversibility 
of the reaction, simply stated: CaS x +2H 2 O^Ca(OH) 2 +H 2 S+ 
(x — 1)S. In Experiment 1 we evidently have quantitative data 
relative thereto. The course of the equation from left to right is a 
matter of hydrolysis and the reaction evidently will progress thus 
in all solutions until inhibited by the accumulation of hydrogen sul- 
phid, provided the latter is not allowed to escape. The more dilute 
