Materials and Formulas. 141 



COPPER CARBONATE AND AMMONIUM CARBONATE MIXTURE. 

 This mixture was proposed by Chester in 1890. He thought 

 it possible that ammonia might not be the best solvent of 

 copper carbonate and the following formula uses ammonium 

 carbonate in place of ammonium water. The resulting fun- 

 gicide is nearly identical with copper carbonate dissolved in 

 ammonia, and the remarks regarding that fungicide also apply, 

 iii the main, to this preparation : 



Copper carbonate 3 ounces. 



Ammonium carbonate 1 pound. 



Water 40-45 gallons. 



"By this combination all the copper is completely dissolved. 

 To test the question, I prepared the above fungicide with the 

 exception that I took 5 ounces of the copper carbonate in order 

 to have an excess. An analysis showed that the 1 pound of 

 ammonium carbonate had dissolved 3.11 ounces of the original 

 copper carbonate." 1 



Ammonium carbonate can be bought for fifteen to thirty 

 cents per pound. 



COPPERAS. See IRON SULPHATE. 



COPPER CHLORIDE; CuCL 2 . The chloride of copper has 

 received little attention as a fungicide, although it is a prom- 

 ising compound. It contains 46.93 per cent of actual cop- 

 per. When used alone it is very caustic to foliage, a solution 

 of 1| ounces in 25 gallons of water being too strong. Two 

 or three times its bulk of lime should be added, when 5 ounces 

 to 25 gallons of water will prove a satisfactory proportion. The 

 undissolved crystals must be kept in tightly closed glass vessels, 

 as they absorb water rapidly, and are soon reduced to a liquid 

 condition. The chemical is at present too expensive for general 

 use. 



COPPER SODA MIXTURE. See COPPER CARBONATE. 



COPPER SODIUM HYPOSULPHITE ; 2 N"A 2 S 2 O 3 , Cu 2 S 2 O 3 . This 

 material may be prepared as follows : " Dissolve 8 ounces of sul 

 phate of copper in hot water, then dilute with cold water, to about 

 10 gallons. In another vessel dissolve 1 pound of hyposulphite of 



1 Chester, Del. Agric. Exp. Sta. Utli Ann. Kept. 1891, 71. 



2 For a more complete discussion of this fungicide, see Del. Agric. Exp. Sta. 

 Uth Ann. Rept. 1891, 73. 



