10 
SPICES 
CHAP. 
bluestone ” or “ agricultural sulphate of copper ” must be 
avoided, as these are usually adulterated with iron sulphate. 
The strength of Bordeaux mixture at present most widely 
recommended in the United States is 4f lb. of copper 
sulphate, 4f lb. of quicklime, 50 gallons (Imperial) of water. 
This strength is expressed in America by the formula 4:4:50, 
since, as Mr. Pickering has lately pointed out, the relative 
value of the American and Imperial gallon is different, the 
former weighing 8 -345 lb. and the latter 10 lb. As, however, 
excellent results have followed the use of Bordeaux mixture 
made of the strength 4:4:50 (Imperial), it would seem advisable, 
for the present, at any rate, to continue to use this as the 
“ standard ” mixture. 
Dissolve the 4 lb. of copper sulphate in a wooden tub or 
bucket — iron or tin vessels must not he used. The easiest way 
to do this is to suspend the material, wrapped in a piece of 
coarse sacking, in a few gallons of cold water, from a stick 
placed across the top of a tub, or wooden bucket. If this be 
done over night, the copper sulphate will be found to be 
dissolved in the water by the morning. (If hot water be used, 
the copper sulphate can be placed at the bottom of the tub or 
bucket, and be dissolved in a few minutes.) Then add the 
water to make 25 gallons. Uow take the 4 lb. of quicklime, 
and put it in a tin pail. Add a few pints of water till all the 
lime is slaked, taking care to add only a little water at first ; 
in this way a thick creamy paste is obtained. Add water to 
make 25 gallons. We have now 25 gallons of copper sulphate 
solution, and 25 gallons of “ milk -of -lime.” When the two 
substances are thus diluted with water, they can be mixed 
together by pouring one into the other, or a bucketful of each 
can be poured simultaneously or alternately into a third tub 
— a wooden bucket being used for the copper sulphate solution. 
The “ milk-of-lime ” must be well strained, and it is advisable 
also to strain the Bordeaux mixture before spraying. In this 
way we obtain 50 gallons of Bordeaux mixture of the best 
quality. 
Two points are of primary importance in making Bordeaux 
mixture. The first is that quicklime, in lumps, that is to say, 
as freshly burnt as possible, should be used. Powdered air- 
slaked lime, such as is often found in builders’ yards, will not 
make Bordeaux mixture. The second point to observe is that 
the two constituents, viz. copper sulphate and lime, are diluted 
with water as much as possible (consistent with the formula) 
before being mixed together. If concentrated solution of copper 
sulphate and lime are mixed together, and water then added to 
