FORMULAS. 
BORDEAUX MIXTURE. 
Copper sulphate.4 pounds 
Lime.4 pounds 
Water.45 gallons 
The copper sulphate must be dissolved in hot water if wanted 
for immediate use. It may be dissolved by suspending it in a sack 
in the top of a considerable quantity of cold water, but this method 
requires a much longer time. If placed in the bottom of the vessel 
it will not all dissolve. The best quality of stone lime should be 
purchased, slacked and diluted till it is in the form of a thin white¬ 
wash. After the copper sulphate solution has been diluted to about 
thirty gallons, the whitewash is poured in, stirred thoroughly, and 
the mass diluted to the required 45 gallons. It is essential that 
both the copper sulphate solution and the whitewash be quite 
dilute before they are combined, otherwise a coarse precipitate is 
formed, which does not pass through the spray nozzles readily. 
Where large amounts of Bordeaux are to be used, it is advan¬ 
tageous to keep on hand a stock of dissolved copper sulphate and 
of slacked lime. The stock of copper sulphate may be made by 
dissolving, say, fifty pounds in twenty-five gallons of water. Then 
one gallon of the solution will be equivalent to two pounds of cop¬ 
per sulphate, and two gallons will be required for a barrel of the 
mixture. The vessel containing the solution should be kept closely 
covered to prevent evaporation. It should be mentioned, also, that 
copper sulphate corrodes iron quickly, therefore it must not be al¬ 
lowed to come in contact with iron vessels or tools. 
The lime may be slacked in quantities, when it will keep in 
good condition all summer, if it is not allowed to become dry. A 
chemical test for copper is taken advantage of to determine the amount 
of lime paste to be used. This is called the potassium ferrocyanide 
test. The chemical comes in the form of yellow crystals, and a 
few cents worth will suffice for the entire season. It should be dis¬ 
solved in ten times its bulk of water when it is ready for use. A quan¬ 
tity of the lime paste in the form of a thin whitewash is added to the 
dilute copper sulphate solution, then the mixture is stirred thor¬ 
oughly. A drop of the test is now allowed to fall on the surface of 
the mixture. It will instantly turn to a dark, reddish-brown color 
