Trials of Copper Compounds. 27 



first to plan and publish results which showed plainly the value 

 of the copper compounds in commercial work. 1 



The first systematic applications of copper compounds for the 

 prevention of the downy mildew were made 2 on the 18th of 

 August, 1883, or the year following the observation of the ap- 

 parent value of lime and copper sulphate when applied together. 

 The work was done on the grounds of the castle of Danzac in 

 the Medoc, by E. David, steward of the place, but under the 

 direction of Millardet. In these experiments the sulphates of 

 iron and of copper were used. They were applied in pure 

 solutions, and also mixed with lime in varying proportions. 



In 1883 Millardet, believing that copper was the most effi- 

 cient agent in the destruction of the mildew, applied this metal 

 in other forms than the sulphate. He used. 3 in addition, the 

 carbonate, phosphate, and sulphide of copper, and also the 

 corresponding salts of iron. Lime was also applied alone. In 

 1884 the same w T ork was repeated, and although the mildew was 

 not very abundant, still he and Mr. David came to the conclu- 

 sion that the mixture of the sulphate of copper and the milk of 

 lime was the most promising of all the materials applied. They 

 decided to give up the use of the iron salts, as well as the sim- 

 ple solution of copper sulphate. It was found that the latter 

 burned the leaves when used stronger than one-half part of the 

 salt in 100 parts of water. This result, however, does not agree 

 with those obtained by Messrs. Ad. Perrey, P. de Lafitte, and 

 Maginen. On the estate of Salle de Pez, at St. Estephe, an 

 8 per cent solution of copper sulphate proved 4 to be nearly as 

 efficient as when lime was added. 



During these two years the mildew was not very prevalent in 

 the treated vineyards, so that only partially satisfactory results 

 were obtained. These were, however, of sufficient value to 

 warrant the publication 5 of an article by Millardet, in which 

 were given the following directions for preparing and applying 

 the mixture : 



" In 100 liters of water dissolve 8 kilos of commercial 



1 Jour. d'Aff. et d'Hort. de la Gironde, Oct. 1. Cited in Jour. d?Ag. Prat. 

 1885, Dec. 3, 804. 



* Jour. d J Ag. Prat. 1885, Dec. 3, 804. 

 Ibid. 708. 



* Ibid. Nov. 5, 661, 662. 



Annales de la Societe d'Ag. de la Gironde, 1885, April 1, 73 et eeq. 



