349 
No. 19.— IRON BORATE MIXTURE. 
(Rows 19 and 19 1 .) 
22.94 grams ferrous sulphate exsiccatus (FeS0 4 , H>0). 
91.76 grams sodium borate (borax) (Na. 2 B. 4 O 7 , 10H 2 O). 
1 gallon of water. 
Chemical notes .—A steel-gray precipitate, becoming brown or yellow on exposure. 
Probably a basic salt of uncertain chemical composition (see Watts’ Dictionary of 
Chemistry, 1888, p. 530). The chemical reaction would be written FeS0 4 , HoO + 
Na 2 B 4 0 7 , 10H 2 O = FeB 4 0 7 -f-Na 2 S0 4 -f- 11H 2 0. The sodium sulphate is in combina¬ 
tion with iron borate in the mixture as sprayed on the plants. 
Remarks .—This mixture is much more difficult of preparation, covers the foliage 
no more effectively, and adheres no more tenaciously than ammoniacal solution. It 
proved almost entirely ineffective in retarding the spread of the disease and was 
highly injurious, scorching the leaves in a few minutes after application. The 
treated rows were 0 and grades better than adjacent untreated rows on September 
2, and 0 and 0 better on October 13. It was the most injurious of any of the mixtures 
employed and has no good qualities to redeem it. 
NO. 20.—FERRIC HYDRATE MIXTURE. 
(Rows 20 and 20'.) 
22.94 grams ferrous sulphate exsiccatus (FeS0 4 , I4 2 0). 
11.47 grams potassium hydrate (KHO). 
1 gallon of water. 
Chemical notes .—The precipitate is of a dirty green color, changing on exposure to 
a rich brown. The ferrous compound, Fe(OI4) 2 , which is formed on adding potas¬ 
sium hydrate to ferrous sulphate, becomes, on exposure to the air, the ferric com¬ 
pound, Fe 2 (OH), ; (see Watts). It is probable, however, that the.green ferrous ferric 
compound Avas that first formed, as the air was not, of course, excluded from the 
mixture. The chemical reaction would be FeS0 4 , H 2 0 -f- 2KHO=Fe(HO ) 2 -f- Iy 2 S0 4 -f- 
H 2 0. The ferric hydrate and potassium sulphate are therefore in combination in the 
mixture. 
Remarks .—This mixture is more difficult of preparation than ammoniacal solution, 
covers the foliage about as well, and adheres as well, but was slightly injurious. It 
proved much less effective in retarding the progress of the disease. The treated rows 
were 0 and \ grades better than untreated adjacent rows on September 2, and 0 and 
0 on October 13. It is doubtful if this mixture has any fungicidal effect whatever. 
No. 21.— IRON SULPHIDE MIXTURE. 
(Rows 21 and 21 1 .) 
22.94 grams ferrous sulphate exsiccatus (FeS0 4 , H 2 0). 
91.76 grams potassium sulphide (liver of sulphur, liepar sulphur). 
1 gallon of water. 
Chemical notes .—This mixture is in the form of an inky black fluid, which, on 
exposure, deposits an orange-yellow precipitate. When the proportion of potassium 
sulphide to ferrous sulphide is as low as three to one there is formed a precipitate in 
the liquid which gradually sinks to the bottom. Baric chloride gives the reaction 
for sulphuric acid in the solution. It is probably a compound of complex composi¬ 
tion, as it is not described by Watts; possibly a potassium-iron sulphide (see 
Watts, 1872, p. 1077). 
Remarks .—This mixture is more difficult to prepare than ammoniacal solution, 
covers the foliage no better, and adheres little if any better. It proved almost 
wholly ineffective in retarding the progress of the disease and was evidently slightly 
injurious to the foliage, although diluted to 2 gallons after the first application. The 
treated rows were 0 and 4 grades better than adjacent untreated rows on September 
2, and 0 and 0 on October 13. Its fungicidal properties, if any, are slight. 
