j^Ew York Agricultural Experiment Station. 431 



Paris green or other arsenicals which are recommended against 

 the insects, may be combined with Bordeaux mixture, but not 

 with the ammoniacal sohition of copper carbonate. 



Ammonical solution of copper carbonate. — The formula usually 

 given for making this solution is as follows : Dissolve five ounces 

 of copper carbonate in three pints of ammonia of 26° strength. 

 \Yhen ready to apply, dilute with water so as to make fifty gal- 

 lons. The undiluted solution may be preserved for some time in 

 tightly closed vessels. 



Penny finds^'^ that the use of the strong undiluted ammonia in 

 dissolving the copper is wasteful and unsafe. He recommends 

 the following method of making the solution. " To one volume 

 of 26° Beaume ammonia (the strong amiuonia of commerce) add 

 from seven to eight volumes of water. Then add copper car- 

 bonate, best in successive quantities, until a large portion remains 

 undissolved. The mixture should be vigorously agitated during 

 the solution and finally allowed to subside, and the clear liquid 

 poured off from the undissolved salt. A second portion should 

 then be made by treating the residue of the former lot with more 

 ammonia diluted as before, then with the addition of fresh cop- 

 per carbonate, in every case with vigorous stirring or agitation. 

 The method of making in successive lots will result in a richer 

 solution of copper, at least unless an unwarranted length of time 

 be taken." He finds that much less ammonia is required to dis- 

 solve a given amount of copper carbonate in this way than ac- 

 cording to the method formerly followed of adding the strong, 

 undiluted ammonia directly to the copper carbonate. 



chlorosis or yellow leaf. 



The name is applied to a grape disease in which the foliage turns 

 yellow, later becoming brown. It is common in some parts of the 

 State. 



2CDol. Agr. Exp. Sta. Bui. 22. 



