500 THE farmers' handbook. 



The lime being i educed to a tine powder, water is added to produce a thin 

 whitewash, and the whole should then he strained through coarse sacking to 

 remove any lumps that may cause trouble in the nozzle. Enough water is 

 then add- d to bring the quantity of milk of lime up to half the total quantity 

 of Bordeaux mixture that is to-be made. In other words, just as the copper 

 sulphate solution was brought up to 25 gallons, so the necessary water is 

 added to the limewash to bring it up to 25 gallons. 



The bluestone solution and the milk of lime are now ready to be brought 

 together. This must be done in such a way as to ensure their being thoroughly 

 mixed. Pouring one into the other is not satisfactory. They should both 

 be poured at the same time into the large vessel mentioned abo\ - e. The 

 operation can be best performed by two men, each with a bucket, one 

 handling the bluestone solution and the other the milk of lime, and both 

 pouring in together and stirring frequently. The sulphate of copper (blue- 

 stone) solution of the lime and water mixture can be kept separately for 

 several days, but when mixed the resultant spray should he used at once, as 

 it deteriorates when kept. 



AVhere Boideaux mixture is to be used regularly, and in fairly large 

 quantities, it is profitable to haye a larger equipment than the above. 



Using a stock solution of copper sulphite made as directed above, 1 gallon 

 of the solution for every 1 lb. of copper sulphate required should be put in a 

 large cask, and correctly diluted with water. The milk of lime must be 

 placed in another cask. Both casks should be on a raised platform, so that 

 their contents can run through their outlet taps or cocks into a third cask 

 twice the size. The third cask should also be on a platform high enough to 

 permit its contents to gravitate quickly through a large tap or cock into the 

 supply or spray cart. It is better to use the third cask as described, rather 

 than to mix direct into the cart, as the mixture can then be strained as it 

 runs from the third cask. "When large quantities are being dealt with, one 

 man can be mixing while another is carting out. The size of the mixing 

 casks is governed by the size of the tank of the spray outfit. For instance, 

 it the tank's capacity is 100 gallons, two 50-gallon casks and one 100-gallon 

 cask could be used. But as 100-gallon casks are often not obtainable ready 

 made, four 25-gallun casks and two 50-gallon ones will serve the purpose. To 

 accelerate the supply the number of sets of casks is increased. The smaller 

 casks should have the 25-gallon level accurately and plainly marked in two 

 places on opposite sides of the interior : a countersunk hole or a short nail 

 driven part of the way home answers the purpose Larger casks should have 

 the 50-gallon level marked in a similar way. 



The object of Bordeaux mixture is to apply copper sulphate to the potato 

 plants so that it may attack fungi that happen to be growing thereon ; but 

 it also attacks the plant tissue, and the lime is added to neutralise it, and 

 prevent harm being done. The proportions mentioned in the above formula 

 supply ample lime to more than neutralise all the copper sulphate, provided 

 that the lime is pure, that it is freshly burnt, and that it is all made into 

 milk of lime. It not infrequently happens that one of these three conditions 

 is not complied with, and sometimes not more than half the quantity of lime 

 recommended actually becomes combined with the copper sulphate. In such 

 cases there will be free copper sulphate in the spray, and it will then be liable 

 to injure the crop. It is desirable, therefore, to know whether the copper 

 sulphate has been completely neutralised. 



