864 



Agricultural Gazette of N.S.W. [Oct. 2, 1908. 



The Bordeaux mixture must be made tlius : — Dissolve 10 o/.. of copper 

 sulphate in 1 gallon of water by suspending it in a piece of sacking. This 

 must be done in a wooden or earthenware vessel. Take some good (juicklime, 

 slake it in a little watei-, and put it into a tub with about 20 gallons of 

 water; the quantity of lime does not matter so long as it is not less than 

 1 or 2 lb. Stir the lime and water up two er three times and leave it to 

 settle till the solution becomes quite clear. If it is left for any length of 

 time the tub should be covered. From this cleai- solution syphon off 

 8 gallons 3 pints, and add to the sulphate of copper solution. Testing the 

 solution for copper must by no means be omitted. 



The kerosene in the above recipe amounts to 1-4 per cent., and may, of 

 course, be reduced or increased according to circumstances. 



The above solution may be made with iron sulphate instead of copper 

 sulphate ; it would be then much cheaper, but would possess no fungicidal 

 properties. 



Green Manuring in Departmental Orchard. 



Test for copper in Bordeaux Mixture. 



Put a few drops of a solution of potassium fcrrocyanidc into u wliite saucer 

 with some watei", and drop into this some of the clear li([uid ubtained after 

 the Bordeaux mixture has been allowed to settle; any brown or red colora- 

 ti<m indicates that there is copp(M' in solution, and a little nioic lime wati'i- 

 must be then added to the mixture and the test repeated. 



A wire nail, free from grease, dipped into the Bordeaux mixture will, if 

 there is any unprecipitated copper present, lu'come coated witli a deposit of 

 copper which appears like a stain mi tlie iinn ; a bright knife blade isunsuit 

 able as it does not become wet. 



With the iron nail test, '05 per cent, of coppei- sulphate may be detected, 

 but with the ferrocyanide, '005 per cent., or even -002 per cent., when more 

 delicate means of observing the colour are employed. 



No more lime-water should be added than necessary to l)ring alxiut complete 

 precipitation. 



