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Ammoniacal Copper Carbonate Solution. 



Penny has made a very careful study of the best method of prepar- 

 ing this solution, and the results of his work are here given in full : — 



" The practical directions are these : To 1 volume of 26° Beaume 

 ammonia (the strong ammonia of commerce) add from 7 to 8 volumes 

 of water. Then add copper carbonate, best in successive quantities, 

 until a large portion remains undissolved. The mixture should be 

 vigourously 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 

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

 This method of making in successive lots will result in a richer solu- 

 tion of copper, at least, unless an unwarranted length of time be taken. 

 This soution may be made in any suitable wooden or stoneware vessel. 



" A still better way is to place in a large jar an inverted crock, or 

 other suitable shelf, and on this the copper carbonate, so that it shall 

 be at the surface of the ammonia when it is poured in. After adding 

 the ammonia, diluted as above, the whole should be allowed to stand 

 covered some time, as over night, and then the undissolved copper salt 

 may be in great part easily lifted out of the solution. Instead of the 

 shelf a suitable receptacle may be used, as a fine wire sieve. The jar 

 will need nothing but a loose cover, as the loss of ammonia will be 

 slight at that degree of dilution. 



"The clem* solution thus obtained, containing from three to four per 

 cent, of ammonia gas, must be diluted as described above, in no case 

 less than 13 or 15 fold, better, for the safety of the plant, 20 fold or 

 more. 



" Those directions which recommend so much ammonia, (whatever 

 it may be) to be used as may be necessary to dissolve the copper salt 

 and then to dilute to a given number of gallons, are not only not 

 economical, but absolutely dangerous, in as much as it is an uncertain- 

 ty just how much ammonia may be used in the first instance, and hence 

 uncertain what strength it may have after dilution, when applied to 

 the trees. It should be borne in mind always that if strong ammonia 

 is used it must be diluted from first to last at least 100 fold, and bet- 

 ter considerably more. 



" The solubility of copper carbonate in ammonia carbonate has been 

 studied but not yet sufficiently for report. 



After the copper carbonate has been dissolved in ammonia water, it 

 should be used by taking as much of the fluid as contains 1 ounce of 

 dissolved copper carbonate, and this is then diluted with 9 gallons of 

 water. These proportions should be retained when either larger or 

 smaller quantities of the fungicide are desired. 



The ammoniacal solution of copper carbonate possesses some decided 

 advantages. It is a clear solution entirely free from sediment, and can 

 therefore be applied as readily as water. Another favourable point is 

 that it may be used quite freely upon maturing fruit, and also upon 

 flowering plants, without leaving any conspicuous stain. When cer- 

 tain plants require spraying with a fungicide shortly before the crop 

 is harvested, this preparation is an excellent one to use. In efficiency 

 it also ranks high, being clearly surpassed in this respect only by the 



