PROTECTING PLANTS 197 
and add water to make the required amount. Experiment stations 
often recommend the diluting of both the copper sulfate solution and 
the lime mixture to one-half the required amount before pouring to- 
gether. This is not necessary, and is often impracticable for commer- 
cial work. It is preferable to dilute the copper sulfate solution. Never 
pour together the strong stock mixtures and dilute afterward. Bor- 
deaux mixture of other strengths, as recommended, is made in the same 
way, except that the amounts of copper sulfate and lime are varied. 
(4) It is not necessary to weigh the lime in making bordeaux mix- 
ture, for a simple test can be used to determine when enough of a stock 
lime mixture has been added. Dissolve an ounce of yellow prussiate 
of potash in a pint of water and label it “poison.” Cut a V-shaped 
slit in one side of the cork so that the liquid may be poured out in drops. 
Add the lime mixture to the diluted copper sulfate solution until the 
ferro-cyanide (or prussiate) test solution will not turn brown when 
dropped from the bottle into the mixture. It is always best to adda 
considerable excess of lime. 
“Sticker” or adhesive for bordeaux mixture. — Resin, 2 lb.; sal soda 
(crystals), 1 Ib.; water, 1 gal. Boil until of a clear brown color — one 
to one and one-half hours. Cook in iron kettle in the open. Add 
this amount to each fifty gallons of bordeaux for onions and cabbage. 
For other plants difficult to wet, add this amount to every one hun- 
dred gallons of the mixture. This mixture will prevent the bordeaux 
from being washed off by the heaviest rains. 
Ammoniacal copper carbonate. — Copper carbonate, 5 oz.; ammo- 
nia, 3 pt.; water, 50 gal. Dilute the ammonia in seven or eight parts 
of water. Make a paste of the copper carbonate with a little water. 
Add the paste to the diluted ammonia, and stir until dissolved. Add 
enough water to make fifty gallons. This mixture loses strength on 
standing, and therefore should be made as required. It is used in 
place of bordeaux when one wishes to avoid the coloring of maturing 
fruits or ornamental plants. Not as effective as bordeaux. 
Potassium sulfide. — Potassium sulfide (liver of sulfur), 3 0z.; water, 
10 gal. As this mixture loses strength on standing, it should be made 
just before using. It is particularly valuable for the powdery mildew 
of many plants, especially gooseberry, carnation rust, rose mildew, etc. 
Sulfur. — Sulfur has been found to possess considerable value as a 
