11 Nov., 1918.] Copper Fungicides for Vine Diseases. 675 



water to the 50-gallon level. Solution takes place rapidly; as the crystals 

 dissolve the liquid bathing them becomes more dense and streams to the 

 bottom of the cask and is continually replaced by less concentrated and 

 consequently lighter liquid. Owing to the automatic circulation thus 

 set up, solution is complete in a few hours; after stirring, the cask will 

 wntain 50 gallons of stock solution, which will keep indefinitely, and of 

 which. 5 gallons will be required for each 50 gallons of Bordeaux 

 mixture. 



Stock- Lime Milk. — Take 40 lbs. pure quicklime, make up to 17 

 gallons with water; one gallon of this milk will be required for each 

 50 gallons of spray mixture. 



The specially selected lime packed in air-tight tins, now obtainable, 

 will be found very convenient for the preparation of a stock lime milk 

 of standard strength, such that a definite measured quantity will con- 

 tain a known weight of lime. It has been shown (p. 596) that 2:^ lbs. 

 pure quicklime is sufficient to bring about the first signs of alkalinity 

 in a solution containing 10 lbs. of copper sulphate. The following pro- 

 cedure will be found convenient : — 



Take a tub of about 20 gallons capacity in which the l7-gallon* level 

 is marked with a peg. Tip the contents of a 40-lb. tin of lime into the 

 empty tub and slake in the ordinary way by sprinkling several times 

 with a little water. When thoroughly broken up make up to the 17- 

 gallon level with water; after stirring a few times a milk will be obtained 

 of such strength that one gallon will be the correct dose for 50 gallons 

 of Bordeaux. This milk should be prepared a day or two before use 

 and should be well stirred immediately before each withdrawal. When 

 using, dilute with about four times its bulk of water and pour into the 

 Bordeaux through a fine sieve to get rid of gritty particles; unless thus 

 diluted it will be found difficult to strain at the above concentration. 

 When making the Bordeaux, test occasionally with phenolphalein paper 

 to make sure that neutralization is complete; if the paper does not turn 

 pink add a litrle more lime milk. This is specially important when 

 casein is to be added; unless the Bordeaux be at least slightly alkaline 

 the casein solution would be curdled. 



If commercially pure lime be not obtainable, a stock milk may yet 

 be made up with ordinary quicklime — the fresher the better — exactly 

 as described above. It will be found, however, that rather more than 

 one gallon of the resulting milk will be required for each 10 lbs. blue- 

 stone (50 gallons of Bordeaux),) how much more will depend on the 

 quality of the lime. When mixing the first 50 gallons of Bordeaux a 

 record should be kept of the quantity of lime milk needed to induce the 

 first signs of alkalinity (test paper turns pink). A similar quantity 

 will naturally be needed for each 50-gallon lot. 



Casein Stock Solution. — Take 10 lbs. casein, dissolve with the aid of 

 either lime or washing soda and make up to 4 gallons with water. One 

 pint — a pannikin is a convenient measure — will suffice for each 50 

 gallons of spray. The solution may be made in two different ways. 



(1) Mix the casein with about an equal bulk of dry slaked lime. 

 Take a small basin, fill about three parts full with water, tip the mix- 

 ture of lime and casein on to the surface of the water. If an ordinary 



* strictly speaking it should be 175 gallons. Even the test lime usually contains about 5 per cent, 

 imparities : the reduction of the " milk " by J gallon will approximately compensate for this. 



