New York Agricultural Experiment Station. 383 

 Fungicides. 



Ammoniacal Solution of CoppiiiR Carbonate. — The formula 

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

 ounces of cojDper carbonate in three pints of ammonia of 26° 

 strength. When ready to apply, dilute with water so as to make 

 fifty gallons. The iindikited solution may be preserved for some 

 time in tightly closed vessels. 



Penny finds'" that the use of the strong ammonia undiluted 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 ammonia of commerce) add from 

 seven to eight volumes of water. Then add copper carbonate, 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 treat- 

 ing the residue of the former lot with more ammonia diluted as be- 

 fore, then with the addition of fresh copper carbonate, in every case 

 with vigorous stirring or agitation. The method of making in suc- 

 cessive lots will result in a richer solution of copper, at least unless 

 an unw^arranted length of time be taken." fie finds that mucli less 

 ammonia is required to dissolve a given amount of copper carbonate 

 in this way than according to the method formerly followed of 

 adding the strong, undiluted ammonia directly to the copper car- 

 bonate. 



Bordeaux Mixture. — This is made of various strengths. Suc- 

 cessful results have been obtained at this Station and elsewhere with 

 the 1 to 11 formula, that is to say with a mixture using one pound 

 of copper sulphate for eleven gallons, and this is recommended for 

 most i^ui'poses. In treating potato blights better results have been 

 obtained from a stronger mixture, using the 1 to 7 formula, that is 

 to say, one pound of copper sulphate for seven gallons of the 

 mixture. 



The formulne referred to in this discussion may be given as follows : 



1 to 7 formula : One lb. copper sulphate ; I lb. lime, fresh 

 slaked ; 7 gallons water. 



17 Bull. 22, Del. Exp. Sta. 



