308 STATE HORTICULTURAL SOCIETY. 



calcium. It seems that a small amount of copper is held in solution in 

 this last form, one rich in the sulphate of copper. 



" A number of experiments have also been made to determine which of 

 the copper salts found in the Bordeaux mixture can be dissolved by atmos- 

 pheric agents. 



" The hydrate of copper was separated as already described, and 

 thoroughly washed. It was then put into a small amount of distilled 

 water. Through this mixture a stream of dried carbonic acid gas was 

 passed for a few minutes and the liquid was again filtered. The filtrate, 

 when tested for copper, revealed considerable quantities of the metal. 

 After a short time the solution became turbid and soon deposited almost 

 all the dissolved copper, undoubtedly because of the rapid decomposition 

 of the bicarbonate which had formed at first. 



" Similar experiments were made with the basic sulphate, after it had 

 been entirely freed from the sulphate of calcium and thoroughly washed. 

 It was then treated with a solution of the hydrate of potash. Carbonic 

 acid gas was again applied, and in this case it caused the solution of much 

 greater amounts of the copper. The filtrate in addition showed also a 

 remarkable quantity of sulphuric acid. The liquid again became turbid, 

 but much larger quantities of copper remained in solution. It seems to 

 me that this circumstance can be explained by admitting that the carbonic 

 acid gas acted upon the basic sulphate causing the formation of the car- 

 bonate of copper, which in part remained insoluble, and in part passed 

 into solution on account of the presence of the gas, and the sulphate of 

 copper. 



" Copper in the form of the sulphate should be more efficacious than 

 when it is precipitated as a hydrate, but the conditions which would 

 cause a larger amount of it to be formed must still receive careful study." 



SUMMARY. 



1. The apple-scab fungus, Fusicladium dendriticiim, attacks apple 

 trees very early in the season, even before the petals fall to the ground. 



2. The first application of a fungicide should be made early, no later 

 than immediately after the petals fall; an application made just before the 

 buds open would probably be of value. 



3. The time for combating the apple-worm is immediately after the 

 petals fall, and the treatment should be repeated once or twice until the 

 apples begin to hang down. 



4. Apple trees should be pruned so that all parts may easily be reached 

 by a spray ; well pruned trees allow free access of light and air among their 

 branches, which prevents fungi from obtaining so strong a foot-hold. 



5. The injury done by the apple-scab fungus was decidedly reduced 

 where the Bordeaux mixture was used. 



6. When Paris green was added to the Bordeaux mixture the fungicidal 

 action of the combination was more marked than when London purple was 

 used in place of Paris green. 



7. Paris green has a certain fungicidal value, but in this respect it does 

 not nearly equal the Bordeaux mixture. 



8. The value of Paris green as an insecticide does not appear to be 

 materially affected, whether it is applied alone or in combination with the 

 Bordeaux mixture. 



