278 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



by plants, or by water containing carbonate of ammonia or carbonic 

 acid. The amount dissolved being very small, the plant is never in 

 contact with a p nsonous amount of soluble copper salt, and bouillie 

 bourguignonne does not burn, except when prepared with a great 

 excess, or with an insufficient amount of carbonate of soda. In making 

 bouillie bourguignonne, not more than 2 kilogrammes of blue vitriol 

 should be used. This quantity is already very strong, and as was the 

 case in other bouillies it has been reduced in modern bouillie bourguig- 

 nonne to 0-3 per cent. Carbonate o' copper fr<'shly prepared by 

 mixing cold solutions of the ingredients is gelatinous, and it is pre- 

 ferably in this form that it should be spread on the leaves to get the 

 maximum adherence and produce the best eti'ect ; as it does not 

 preserve this gelatinous condifon long, the bouillie must be used 

 immediately after it is made. In fact after eight to ten hours copper 

 carbonate becomes granular, and ends by being converted into a heavy, 

 sandy precipitate, and thus the bouillie loses a portion of its good 

 qualities. This conversion would appear to be accelerated by an 

 excess of carbonate of soda. It already happens when 2-6 kilo- 

 grammes of soda crystals are u^ed for 2 kilogrammes of blue vitriol, 

 whilst with 2-3 kilograms, the theoi'etical amount required, this 

 conversion does not occur until after twenty-four hours. Many 

 bouillies are thus intentionally made with a small excess of blue 

 vitriol, which cannot injure the plant, and which strengthens slightly 

 its action on fungi, if bouillie bourguignonne be made hot, the 

 resulting carbonate of copper is granular and crystalline. Its anti- 

 cryptogamic action is perceptibly inferior to that of gelatinous copper 

 carbonate. A bouillie is often used prepared with 0*4 per cent of 

 blue vitriol and O-l per cent of soda crystals, or even 0-3 per cent of 

 blue vitriol with the same amount of soda crystals. Commercial 

 copper carbonate always granular, though excellent to prepare 

 modified eau celeste, is unsuitable for the preparation of a normal 

 bouillie bourguignonne. If nevertheless it is to be used, it must first 

 of all be reduced to the state of paste by means of a little water, 

 adding thei-eto whilst stirring the rest of the water, keeping the 

 bouillie generally more concentrated than those obtained by pre- 

 cipitation from blue vitriol. The adherence of this bouillie is much 

 less than that of bouillie bourguignonne prepared from blue vitriol. 

 Gerard, Muy.ssen, and Leplee consider gelatinous carbonate of copper 

 adheres better than cupric hydrate, and the duration of the action 

 longer than that of bouillie bordelaise. This difference was especially 

 marked when the bouillie bordelaise contained a great excess of lime. 

 However the adherence of a neutral bouillie bordelaise may now be 

 considered as great as that of a normal bouillie bourguignonne. 



Use. — Its ready preparation, its uniform composition, its good 

 adherence, its great fluidity not obstructing the spraying machines, 

 have greatly helped to popularize Masson's bouillie, and it has met 

 with a general reception, especially in Germany and in America. It 

 may be used with an equal blue vitriol content, wherever bouillie 

 bordelaise gives good results. It is especially recommended in certain 

 cases. Weiss regards it as superior in the disinfection of purchased 



