370 
are poured together in the spray tank or barrel and again thoroughly 
stirred.* In making the mixture from diluted solutions it is best to 
have two vessels, each holding half as much as the tank; the proper 
amount of copper sulphate and lime stock can be measured out and 
each diluted without the trouble of measuring the water added. The 
superior quality of Bordeaux mixture made in this way will fully repay 
any extra labor of making. It does not suffice to dilute only one of 
the constituents. 
KEEPING QUALITIES OF BORDEAUX MIXTURE. 
The sooner the Bordeaux mixture is used after being made, the bet¬ 
ter. Changes in the precipitate soon begin; it eventually becomes 
coarsely granular, settles very quickly, and adheres very poorly to the 
foliage. Probably no serious degeneration of the mixture takes place 
inside of three or four hours, but there can be little doubt that it is 
decidedly of inferior quality after standing twenty-four hours. 
ADDITION OF SOAP TO BORDEAUX MIXTURE. 
As lias been found by G-allowayf and Fairchild, the addition of soap 
to the mixture greatly increases its wetting properties, and makes it 
much better for spraying plants having a waxy cuticle, and lienee diffi¬ 
cult to wet thoroughly. The exact nature of the chemical changes 
produced by adding soap is as yet almost unknown. The practice 
has been to add soap in solution until an abundant and permanent foam 
is produced upon stirring the mixture violently. Usually a consider¬ 
able quantity of soap is required to produce this effect, about half as 
much as the total weight of copper sulphate and lime used. The soap 
should be in solution; with hard soaps it is best to shave into thin 
slices, dissolve in hot water, and add to the finished mixture warm. 
Soft soaps may be diluted and added cold.f 
* For instance, in making given stock solutions containing 2 pounds of copper 
sulphate or lime to the gallon, in making a mixture of the strength of 6 pounds of 
copper sulphate and 3 pounds of lime to 50 gallons, the procedure would he as fol¬ 
lows: Take 3 gallons of the stock copper sulphate solution and dilute with 22 gal¬ 
lons of water, making 25 gallons in all; after stirring well it is ready for use. Take 
U gallons of the stock milk of lime and dilute with 23J gallons of water, making 
25 gallons. A mark can readily he made showing to what point the barrels are filled 
and rendering it unnecessary to measure the water added after the first time. After 
stirring both the diluted solutions well, pour them at once into a tank or barrel, 
straining through close-meshed wire netting. The mixture should now be thor¬ 
oughly stirred with a broad paddle for at least two minutes. 
tGalloway, B. T. Experiments in the treatment of rusts affecting wheat and 
other cereals. <Jour. of Mycol., vol. vii, No. 3, May 1893, pp. 195-226. 
fin this connection I would suggest that the very cheap resin soaps be given a 
thorough trial for this purpose. Take 2 parts of resin and 1 part of crystallized sal 
so;la (sodium carbonate, Na 2 OOs, 10H 2 O), melt together in a kettle, stirring until all 
lumps disappear; then dilute with about 4 parts of hot water, which will make a 
stock solution containing 3 pounds of the soap to the gallon. This should be diluted 
