172 FRUIT FARMING 



HOW TO MAKE BORDEAUX MIXTURE. 

 This mixture, so invaluable for all fungoid diseases, 

 has recently been the subject of chemical investiga- 

 tion, and one result has been that a much simplified 

 method of preparation has been worked out, which 

 greatly increases, on the one hand, its fungicidal 

 properties, and on the other, entirely prevents the 

 absence of those small particles of lime which formed 

 when made in the old way, which were a source of 

 trouble in the syringe and sprayers. To make 100 

 gallons take 6-lb. 6J-ozs. of pure crystallised copper 

 sulphate, and dissolve it in a wooden or earthenware 

 tub containing two or three gallons of water. It 

 should be suspended in a rough bag or sack to assist 

 rapid dissolution ; then take some 5-lb. of good quick 

 chalk lime, slake it with a little water, and put it 

 into a tub containing 120 gallons of water. Stir two 

 or three times, and leave it to settle till the water is 

 quite clear. Now run off 86 gallons of the clear 

 liquid, and mix it thoroughly with the copper sulphate 

 as made above. The mixture must now be tested. 

 Place a few drops of potassium ferrocyanide in a 

 white saucer, and drop into this some of the clear 

 liquid obtained after the Bordeaux Mixture has been 

 allowed to settle. Any red or brown coloration 

 indicates that there is copper in solution, and a little 

 more lime water must then be added to the mixture, 

 and the test repeated until no change of colour is 

 observed. But it cannot be too much emphasised 

 that every extra gallon of lime water added beyond 

 that necessary means so much loss of efficiency. 

 This method of preparing Bordeaux Mixture makes a 

 slightly stronger wash than the old method, and to 



