794 



Bordeaux Mixture. 



[JAN., 



coarse sacking, in a few gallons of cold water, from a stick 

 placed across the top of a tub, or wooden bucket. If this be 

 done over night, the copper sulphate will be found to be dis- 

 solved in the water by the morning. (If hot water be used, 

 the copper sulphate can be placed at the bottom of the tub or 

 bucket, and be dissolved in a few minutes.) Then add 

 water to make twenty-five gallons. Now take the four 

 pounds of quicklime, and put it in a tin pail. Add a few 

 pints of water until all the lime is slaked, taking care to add 

 only a little water at first ; in this way a thick creamy paste 

 is obtained. Add water to make twenty-five gallons. We 

 have now twenty-five gallons of copper sulphate solution, 

 and twenty-five gallons of "milk-of-lime." When the two 

 substances are thus diluted with water, they can be mixed 

 together by pouring one into the other, or a bucketful of 

 each can be poured simultaneously or alternately into a third 

 tub, — a wooden bucket being used for the copper sulphate 

 solution. The "milk-of-lime" must be well strained, and it 

 is advisable also to strain the Bordeaux mixture before 

 spraying. In this way we obtain fifty gallons of Bordeaux 

 mixture of the best quality. 



Two points are of primary importance in making Bordeaux 

 mixture. The first is that quicklime, in lumps, that is to say, 

 as freshly burnt as possible, should be used. Powdered air- 

 slaked lime, such as is often found in builders' yards, will not 

 make Bordeaux mixture. The second point to observe is 

 that the two constituents, vis., copper sulphate and lime, are 

 diluted with water as much as possible (consistent with the 

 formula) before being mixed together.* If concentrated solu- 

 tions of copper sulphate and lime are mixed together, and 



* 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 — and 

 more recently in England — 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 s'.irring should be done." 



