346 
Chemical notes. —Necessarily a more or less variable compound from the fact that 
the liver of sulphur is a variable factor, being composed of tri and penta sulphides, 
with the intermediate forms. The most probable formula is Cn 2 S - 2 -f- Cu 2 S : 5 + C 112 S 4 , 
or possibly a mixture of Cu 2 S and Cu 2 S 5 (see Watts, Ibid., 1864, p. 76). Cupric sul¬ 
phate seems to be present in slight excess, and from the reaction it is evident that 
this is combined in the solution with potassium sulphate. 
Remarks. —This fungicide is only slightly more difficult to prepare, covers the foli¬ 
age about as well, and adheres better than the ammoniacal solution. It proved infe¬ 
rior to the ammoniacal solution in retarding the disease, and injured the foliage. 
The treated rows were 1 aud 1 grades better than the adjacent untreated rows on 
September 2, and 1 and 0 on October 13. Although much was hoped for from this 
mixture when first prepared, the experiment has not shown it to possess any remark¬ 
able fungicidal value. 
No. 11.— COPrEll SUCRATE MIXTURE. 
(Rows 11 and 11'.) 
14.90 grams cupric sulphate (C11SO4, 5H 2 0). 
14.90 grams cane sugar (Ci 2 H 22 0u). 
14.90 grams potassium hydrate (IvHO). 
1 gallon of water. 
Cupric sulphate is dissolved in water and the cane sugar is added. The two are 
heated to boiling and then the potassium hydrate is added. All solutions are 
strongly concentrated. 
Chemical notes. —This mixture proved troublesome to make, from the fact that the 
“sucrate” if heated too much after the addition of the potassium hydrate became 
bright red, turning to the red oxide. When properly prepared the mixture is a 
dark, livid green. The reactions are too complex to be written. Evidently little 
is known of the exact composition of this peculiar compound, which differs entirely 
from that formed in the cold. It is not the “ cooper saccharate” of various French 
authors. 
Remarks. —This mixture is much more difficult to prepare than ammoniacal solu¬ 
tion, does not cover foliage any better, and is more easily washed off. It proved 
less effective in retarding the disease and injured the foliage slightly. The treated 
rows were 0 and | grades better than adjacent untreated rows on September 2, and 
1J and 0 on October 13. It is so complex aud difficult of preparation as not to 
warrant further trial. 
No. 12.— COPPER SILICATE MIXTURE. 
(Rows 12 and 12'.) 
14.90 grams cupric sulphate (CuS0 4 , 5H 2 0). 
44.70 grams sodium silicate (Na 4 Si 04 (?)) (Prescott and Johnson, l. c.J 
p. 215, water glass). 
1 gallon of water. 
Chemical notes. —According to the chemical catalogues, water glass is a pure sodium 
silicate. No cupric sulphate could be detected in the supernatant fluid. It is a 
compound of which nothing definite seems to be known. It is not mentioned by 
Watts. The chemical reaction would be 2 CUSO 4 , 5H 2 0 -f- Na 4 Si 04 = Cu 2 Si 04 -f- Na 4 
(SO4) 2 , -f- 5H 2 0. Accordingto this the compound sprayed upon the plants would be a 
mixture of copper silicate and sodium sulphate. 
Remarks. —This mixture is slightly more difficult than ammoniacal solution to pre¬ 
pare, covers the foliage about as well, but does not adhere as well. It proved much 
less effective in retarding the progress of the disease, but was not injurious. The 
treated rows were 0 and 0 grades better than adjacent untreated rows on September 
2, and £ and £ better on October 13. It merits further trial only in a more concen¬ 
trated form. 
