Bitter Pit in Apples. 385 



One per 100,000. No perceptible poisoning effect. 



Calcium sulphate gave exactly similar results to magnesium 

 sulphate with Rome Beauty apples. 



Bariu77i Chlorate. — 



Prepared Jonathans. — In solution for one week, and examined 

 after two weeks in air. 



One per 10,00'0. Pits 1-4 mm. diameter and 1-3 mm. deep. 



One per 100,000. From superficial browning to pits 1 mm. 



One per 1,000,000. No perceptible development of pits or 

 browning. 



Prepared Rome Beauty. — One week in solution, one week in 

 air. 



One per 1000. Dark, well-developed pits 1-3 mm. deep. 



One per 10,000. From superficial browning to pits 1 mm. 

 deep. 



One per 100,000. From slight superficial bi owning to no 

 effect. 



One per 500,000. No perceptible poisoning action. 



Potassium Chlorate. — 



Prepared Jonathans. — One week in solution, and examined 

 after two weeks in air. 



One per 10,000. From superficial browning to slight pit for- 

 mation, none exceeding 1 mm. deep. 



One per 100,000. No perceptible poisoning action. 



Prepared Rome Beauty. — In solution one week and air one 

 week. 



One per 1000. From supei-ficial browning to pits 2 mm. deep. 



One per 10,000. From slight superficial browning to pits 

 0.5 mm. deep. 



One per 50,000. No perceptible poisoning action. 



Of these four salts the barium one is most poisonous^, the 

 magnesium and calcium next, while potassium is one of the 

 least poisonous. The last three are all essential elements of the 

 plant's food, but as we shall see later they do not exercise the 

 same poisonous action when they are present jointly in the pro- 

 per proportions, as when present singly. In addition, with the 



1 Mr. Wilkinson informs me that barium is more commoiili' present in soils than is 

 generally supposed. 



