New York AGRICULTURAL EXPERIMENT STATION. 379 
per ct. or more of magnesium oxide, there would be an accumu- 
lation of magnesium compounds in the sediment, and the re- 
sult of using the sediment repeatedly would not be good econ- 
omy. The wise course is to use only commercial lime that is 
free from magnesium oxide or nearly so. 
EFFECT OF USING MAGNESIUM OXIDE IN PLACE OF LIME IN 
THE LIME-SULPHUR MIXTURE. 
In one experiment, magnesium oxide was substituted for 
lime, using 125 parts of sulphur and an amount of magnesium 
oxide equivalent to 65 parts of lime. The mixture thus pre- 
pared contained only a trace of sulphur in solution. Practi- 
cally no reaction took place. The sediment contained 67.37 
per ct. of sulphur, of which 66.73 per ct. was unchanged sul- 
phur, there being a slight amount of sulphite and sulphate sul- 
phur. In addition, the sediment contained about 20 per ct. 
of magnesium oxide. It was noticed that hydrogen sulphide 
(H.8) gas was formed in considerable amounts. 
It is evident, therefore, that magnesium oxide is not an avail- 
able material for making soluble sulphides. When present in 
lime, it not only forms no sulphides but tends to decompose 
and decrease the amount of calcium polysulphides formed, and 
it causes some actual loss of sulphur through the formation 
and escape of hydrogen sulphide gas. In order to secure the 
most economical results in every way in making the lime-sul- 
phur wash, it is highly desirable, therefore, to use lime as free 
as possible from magnesium oxide. 
EFFECT OF ADDING MAGNESIUM OXIDE TO A DILUTED LIME- 
SULPHUR WASH. 
A concentrated solution of lime-sulphur wash was diluted 
by addition of 9 parts of water, and magnesium oxide was 
added in an amount equivalent to 10 pounds of lime for 50 gal- 
lons of diluted solution. It was noticed, after adding the 
magnesium oxide, that hydrogen sulphide (H,S) gas was freely 
given off. The following tabulated statement gives the amounts 
