286 Report OF THE DEPARTMBNT OF ENTOMOLOGY OF THE 
closely examined once and usually a second time, the spray be- 
ing applied each time to those parts of the trees that had es- 
caped thorough treatment. 
CHARACTER OF THE LIME-SULPHUR-SALT WASH. 
When thoroughly cooked the lime-sulphur-salt wash is a 
heavy, very caustic, brownish or yellowish-green liquid having 
a sulphurous odor. When allowed to stand, the heavy ingredi- 
ents quickly settle, leaving the clear, orange-red liquid. Long, 
brownish crystals soon form in the precipitate. If carefully 
made and thoroughly strained, it sprays about the same as 
standard bordeaux mixture. 
The following analysis, by Mr. F. D. Fuller of the Station 
staff, of a thoroughly cooked sample indicates the chemical 
nature of the wash: 
“In the examination of the lime, sulphur and salt wash, 
special attention was directed toward a study of the combina- 
tion between the lime and sulphur, as it was thought that no 
chemical reaction took place between the lime and salt, but 
rather that the salt was added to raise the boiling point of the 
mixture and possibly effect a more complete combination be- 
tween the lime and sulphur. 
“In the preparation of this wash, the three ingredients are 
boiled together for some time, which causes the sulphur to enter 
into solution combined with the lime in various proportions. 
The orange-red solution which is formed contains the following 
lime compounds: calcium sulphide (CaS), some of the polysul- 
phides of calcium (CaS, and CaS,), calcium sulphate (CaSQ,), 
a large quantity of calcium thiosulphate (CaS, O,) and some 
calcium sulphite (CaSO,). There is quite an excess of lime 
present which settles out on standing. 
“The insecticidal value of this wash is probably due to the 
various sulphur compounds present as sulphides, sulphites, sul- 
phates and thiosulphates, and it is immaterial whether all the 
sulphur is combined thus with calcium or whether some is 
united to sodium. There is no direct evidence that the salt and 
lime react chemically, and it is safe to conclude that the most 
