208 SHADE-TREES IN TOWNS AND CITIES 



bag and suspended in the water so that the salt is just 

 covered. The lime should be dissolved in another vessel, 

 using only a small amount of water at first, adding more 

 as the process of slacking progresses, and then diluting to 

 twenty-five gallons. The copper sulfate solution and the 

 milk of lime should then be poured into a third vessel. It is 

 best to strain the materials when pouring them together. It 

 is important that practically equal amounts of the two solu- 

 tions should be poured together at the same time, otherwise 

 the proper chemical combination may not take place and the 

 results of the spraying may not be satisfactory. 



Ammoniacal Copper Carbonate. In conspicuous places the 

 Bordeaux mixture is objectionable on account of the deposits 

 of lime and copper that remain on the foliage, and therefore 

 ammoniacal copper carbonate is used. It is a clear, light 

 blue solution which leaves no stain. It is not so adhesive to 

 the foliage as Bordeaux mixture, is washed off with heavy 

 rains, and requires frequent renewals. The formula for 

 making it is as follows : 



Copper carbonate 5 oz. 



Strong ammonia 1 qt. 



Water to make 50 gals. 



Dilute the ammonia with two gallons of water, add 

 enough to the copper carbonate to make a thin paste, pour 

 on about half the ammonia and stir thoroughly. Allow the 

 mixture to settle, and then pour off the top, leaving the 

 undissolved portion behind. Repeat this operation, using 

 small quantities of the remaining ammonia until all the cop- 

 per sulfate is dissolved, taking no more ammonia than is 

 necessary to complete the solution. Then add the remainder 

 of the required amount of water. 



