New York AGRICULTURAL EXPERIMENT STATION. 3509 
calcium thiosulphate (CaS,O,), formed in the process of mak- 
ing the wash and also after the wash is prepared if exposed to 
air for some time; and (3) calcium sulphite (CaSO,), formed 
from thiosulphate by taking up oxygen. 
COMPOUNDS OF MAGENESIUM AND SULPHUR. 
Since commercial lime frequently contains considerable 
amounts of magnesium oxide, it is interesting and important 
to know that magnesium does not easily form compounds with 
sulphur like those formed by calcium and cannot therefore 
take the place of calcium. Moreover, magnesium oxide, when 
boiled with water and sulphur, acts as an undesirable agent 
in causing an actual waste of sulphur during the operation of 
preparing the mixture. This is due to the fact that, when 
magnesium hydroxide is boiled with water and sulphur, it 
forms what is known as magnesium sulphydrate (MgsS,H.,), 
which easily decomposes, producing the familiar gas, hydrogen 
sulphide (H.S), known also as hydrosulphurie acid and sul- 
phuretted hydrogen, familiar about sulphur-springs on account 
of its characteristic odor. In the preparation of the lime- 
sulphur mixture with commercial lime containing considerable 
amounts of magnesium oxide, it has been noticed that the of- 
fensive odor of hydrogen sulphide is very prominent over the 
boiling mixture in the kettle. In such cases the same odor 
may be noticed in orchards just sprayed with a lime-sulphur 
mixture prepared with impure lime containing magnesium 
oxide. The sulphur thus converted into hydrogen sulphide gas 
is lost and the preparation contains smaller amounts of the 
desired higher polysulphides of calcium. 
Attention should be called to the fact that hydrogen sulphide 
gas is poisonous when inhaled. One case of poisoning by in- 
halation of this gas during preparation of the lime-sulphur 
mixture has come under our observation. The illness, while 
not serious or prolonged, was uncomfortable. One of the Sta- 
tion employees who has charge of preparing the lime-sulphur 
mixture has stated that during the days he is engaged in this 
work he experiences marked loss of appetite. We believe that 
