Spices / by Henry N. Ridley.

  • Ridley, H. N. (Henry Nicholas), 1855-1956.
Date:
1912
Catalogue details

Licence: In copyright

Credit: Spices / by Henry N. Ridley. Source: Wellcome Collection.

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    make up the 50 gallons, the resulting Bordeaux mixture will be of very inferior quality. The method of mixing described above is that recommended by all scientific authorities in the United States and in our Colonies. Bordeaux mixture prepared by growers in accordance with these instructions has long proved in these countries to be of the greatest value, under practical conditions in the orchard and plantation, in keeping off fungus pests from cultivated plants. According, however, to the recent important investigations of Mr. S. U. Pickering into the nature of Bordeaux mixture, a slightly superior method of mixing the two constituents is “ to take the lime in as weak a condition as possible and, consequently, the copper sulphate in as strong a condition as possible, and to add the copper sulphate to the lime. The ‘ milk-of-lime,’ after being diluted with the bulk of the water and stirred up several times during about half an hour, should be left for the grosser particles to settle before the copper sulphate is added to it, and, after the addition of this, very little more stirring should be done.” Bordeaux mixture is fully efficacious only when freshly made, and will not keep. If more than a day old, it requires to be very thoroughly and constantly stirred while being used, and the use of only freshly-made Bordeaux mixture is far more economical in the long run, and is here strongly recommended. If a considerable quantity of Bordeaux mixture is required for use, the making of stock solutions of copper sulphate and lime, which can be kept through the spraying season and used when wanted, saves both time and labour, and is free from all objections. The stock solutions are made as follows: take two 50-gallon barrels. In one dissolve 50 lb. of copper sulphate in exactly 50 gallons of water. In the other slake 50 lb. of lime by the gradual addition of a little water; to the creamy paste thus obtained add water to make exactly 50 gallons of “milk-of-lime.” These stock solutions will keep for months. Before the “milk-of-lime” is used, the contents of the barrel must be thoroughly stirred, as the slaked lime will have sunk to the bottom. (Care must be taken to stir the “milk-of-lime” very thoroughly each time before measuring it out, so as to get the slaked lime thoroughly in suspension. If this is done there is no difficulty in obtaining the correct quantity of lime per gallon of fluid.) Each gallon which is taken out from the “stock solutions” will be equivalent, respectively, to 1 lb. of copper sulphate or 1 lb. of lime. The required amount of each stock solution is then diluted with water, according to the formula given above, before being mixed together. The “ stock ”