COPPER SULPHATE (BLUE VITRIOL). 215 



are defective from the fact that projected on to the plant, the different 

 densities of the products of which they are composed produces a separa- 

 tion, causing an irregular distribution of the bhie vitriol. On the other 

 hand, powders prepared like " Cupric Sulphosteatite " do not possess 

 this drawback. Besides this drawback preparations which contain blue 

 vitriol have all the defects of its solutions. These drawbacks make them- 

 selves felt when it is a question of using these powders against the 

 cryptogamic diseases which affect delicate plants. The intense scorch- 

 ings may have disastrous et!ects from the point of view of the yield of 

 the plant. But the powders are easily distributed, and that is their 

 great advantage. Their judicious use in special cases may save a 

 vineyard from a sudden attack. The grower sometimes uses powders 

 which enable him to dispense with bouillies, and when the vineyard 

 is far from a dwelling, extensive, and without water, the carting of the 

 necessary water to manufacture these bouillies. The appliances used 

 are those utilized for sulphuration. However, as blue vitriol attacks 

 leather, only bellows with exterior case can be used. In spite of the 

 numerous disadvantages of powders many vine-growers have adopted 

 the cupric sulphosteatite, which is the best of all these preparations. 

 They use it at the same time as the bouillies, but this powder ought 

 not in general to be used, except as a supplement to liquids, when the 

 foliage is so thick that it prevents the uniform penetration of the 

 bouillies. It is good to protect grapes for it penetrates more readily 

 amongst the grapes as compact grains. Exact details will only be 

 given of one of the preparations of this sort, the C7ipric suljjhosteatite, 

 compounded, like Fostite's powder (Povdre Fostite), of blue vitriol 10 

 per cent, talc 90 per cent. It is prepared by pouring on the talc in 

 powder a saturated solution of blue vitriol. The resultant paste is 

 dried, ground, and sifted. It is a bluish powder, which, owing to its 

 lightness, penetrates as far as the interior of the vines with the most 

 dense foliage. Used in the morning dew its adherence is so good that 

 traces of it may be seen two months afterwards, even when violent 

 storms have washed the leaves. Owing to this property it has given 

 perfect results at Montpelier in assuring complete preservation of the 

 vine. It has been especially recommended for destroying the mildew 

 of grapes, for owing to its tenuity it penetrates everywhere, and the 

 rapidity with which it can be applied enables the crop to be saved at 

 the time of a sudden invasion. If it be desired to use it alone for 

 mildew (which cannot be advised in spite of its properties, for bouillie 

 bordelaise is still superior), three applications are necessary, at the 

 rate of 20-25 kilogrammes per hectare (17-6-22 lb. per acre). The 

 first should be done eight days before flowering, the second five weeks 

 after the first, and the third in the middle of July. If there be mildew 

 in the neighbourhood, and late invasions to be feared, supplementary 

 applications must be given. Pulverizations with powders containing 

 blue vitriol are always injurious when they are made during flowering. 

 Amongst the numerous preparations on the market the following may 

 be quoted as intended for making bouillies by mixing them with water, 

 or to be pulverized such as they are by aid of a bellows. Their com- 

 position has been given by Barth, of Colmar : — 



