New YorkK AGRICULTURAL EXPERIMENT STATION. 249 
this ground has been well covered by Chester,?? Fairchild,?* Lode- 
man? and Swingle*® in this country, and by many workers in 
Europe, references to whose work are found in the bibliography at 
the close of this bulletin. Further efforts at study of the chemistry | 
of bordeaux mixture seemed needless. The following presentation 
* 
of the nature of bordeaux mixture is taken from the work of the 
above men. It is hardly necessary to say that this phase of the 
subject is not treated exhaustively; rather, the intention is to make 
the discussion as brief and concise as possible and yet give the main 
facts. 
Bordeaux mixture is made by stirring together a solution of 
copper sulphate and the milk of lime, the latter being obtained 
by adding water to freshly slaked lime. Copper sulphate is acid 
and as such, in any considerable quantity, injures the tissues of 
plants, and the milk of lime is added in sufficient quantities to com- 
bine with all of the copper sulphate so that the mixture gives an 
alkaline reaction. It does not require as much lime by weight to 
secure this alkaline reaction as there is copper sulphate in the mix- 
ture, but in practice at least, equal parts of lime and the copper 
sulphate are used, and a considerably greater excess of lime is very 
commonly used. To secure a proper chemical and physical com- 
bination, chemists recommend that the solution of copper sulphate 
and the milk of lime be greatly diluted before they are combined 
and that both diluted portions be cold. 
The name bordeaux mixture is not confined to any exact formula 
containing the above ingredients, but is given to any mixture of 
copper sulphate, lime and water used for spraying purposes. The 
name comes from Bordeaux, France, where the mixture first came 
in use. The year 1882 is given as the time of the discovery of 
the fungicidal properties of the bordeaux mixture. Several men 
claim the honor of having discovered the fungicidal value of the 
copper compounds, but A. Miullardet*! was the first to plan tests 
and publish results which showed their value in commercial work. 
Its introduction in the United States dates from 1886, when a 
circular was issued from the United States Department of Agri- 
culture calling attention to its merits in controlling diseases of 
grapes. 
*7 Chester (11). * Fairchild (20). 
?Lodeman (37). “Swingle (60). 
*! Millardet (40). 



