B54: REPORT OF THE CHEMIST OF THE 
bonate of lime, and can be added to fresh amounts of sulphur 
and lime in making additional wash. This should not be done 
when the lime used contains magnesium compounds. 
8. Effect of using magnesium oxide in piace of lime in mak- 
ing lime-sulphur wash.— Magnesium oxide does not form 
sulphides when boiled with sulphur. Some limited action takes 
place which results in producing hydrogen sulphide gas. 
When magnesium oxide is present in lime, it tends to decom- 
pose and decrease the amount of sulphides of calcium found. 
Hydrogen sulphide gas thus produced is poisonous and may 
affect unfavorably the person who handles ithe mixture during 
boiling. 
9g. Commercial lime-sulphur preparations.-— Several samples 
of each of four different brands of solutions were examined. 
One brand contained varying amounts of sediment, one sample 
nearly 20 per ct. The percentage of soluble sulphides was 
found to vary from 16.5 to 25.6 per ct.; in most cases the per- 
centage was between 23 and 24. The sulphide compounds 
present were tetrasulphide (CaS,) and pentasulphide (CaS,), 
the proportions varying somewhat; on an average, the two 
compounds were present in approximately equal proportions. 
One sample of a dry powder was examined, the result show- 
ing that at the price charged the cost is higher than in case of 
the commercial solutions. 
