178 THE PRINCIPLES OF AGRICULTURE 



hot water is preferred When completely slaked, or entirely 

 powdered, add more water. When the lime has slaked sufficiently, 

 add water to bring it to a thick milk, or to a certain number of 

 gallons. The amount required for each tank of spray mixture can 

 be secured approximately from this stock mixture, which should 

 not be allowed to dry out. To make Bordeaux. Use 5 gallons of 

 stock solution of copper sulfate for every fifty gallons of Bordeaux 

 required. Pour this into the tank. Add water until the tank is 

 about two-thirds full. From the stock lime mixture take the re- 

 quired amount. Dilute this a little by adding water, and strain 

 into the tank. Stir the mixture, and add water to make the re- 

 quired amount. It is preferable to dilute the copper sulfate solu- 

 tion. Never pour together the strong stock mixtures and dilute 

 afterward. TJie ferrocyanide test. It is not necessary to weigh the 

 lime in making Bordeaux, for a test can be used to determine 

 when enough of a stock lime mixture has been added. Dissolve an 

 ounce of yellow prussiate of potash in a pint of water. Add the 

 lime mixture to the diluted copper sulfate solution until the ferro- 

 cyanide solution will not turn brown when dropped from the bottle 

 into the mixture. It is best to add an excess of lime. 



299ft. Copper carbonate is used as follows: Copper carbo- 

 nate, 1 ounce; ammonia, enough to dissolve the copper; water, 

 9 gallons. Before making the solution, make a paste of the 

 copper carbonate by mixing it with a little water. Use 26 am- 

 monia, and dilute with 7 to 8 volumes of water. Then gradually 

 add the necessary amount to the copper carbonate until all is 

 dissolved. Use only the clear liquid. Dilute as required. For 

 same purposes as Bordeaux, but does not soil foliage or fruit. 



303o. Smut-infested seeds are treated by corrosive sublimate, 

 formalin, copper sulfate, hot water, and other means. For the 

 first, use corrosive sublimate, 1, oz. ; water, 7 gals. It is an effec- 

 tive solution for potato scab. Soak seed potatoes 1% hours. 



Formalin is a gas dissolved in water. Commercially, it has a 

 strength of about forty per cent. One pint dissolved 'in thirty 

 gallons of water is used effectively in preventing potato scab 

 (soak tubers for half an hour, and plant in clean soil), or smut of 

 oats and stinking smut of wheat (soak seed in solution for ten 

 minutes, drain and sow the next day). 



