116 FARM ARITHMETIC. 



grow, pick, grade, pack, and deliver a barrel of fruit. He 

 received $2 a barrel. How much did his orchard pay him 

 in the 12th year ? 



How Spraying Helps. 



Spraying is a very modern farm practice. In a busi- 

 ness way it is scarcely more than 25 years old. During 

 these years a very large number of machines have been 

 invented to lighten the labor of spraying, and to do the 

 work better. Nowadays no good farmer who grows fruit 

 or vegetables neglects to practice spraying. He knows 

 that if he does not spray his crops will be neither so large 

 nor so good. Poisons are used for insects that chew 

 their food ; and oil, dust, or caustics for those that suck 

 the juices of the plants. Various materials are used to 

 prevent diseases attacking cultivated plants. After the 

 diseases have once gained a foothold there is little use in 

 spraying. With both insects and diseases, therefore, pre- 

 vention is better than a cure. 



383. As an experiment a western New York farmer 

 sprayed part of his potato field six times with bordeaux. 

 At harvest time he found that the unsprayed part of the 

 field yielded 150 bushels and the sprayed part 330 bushels. 

 What was the percentage gain due to spraying? 



384. He made two grades of the salable tubers, and 

 found that 60 per cent of the sprayed potatoes could be 

 sold at 40 cents a bushel and the balance at 30 cents, 

 whereas only 40 per cent of the unsprayed salable tubers 

 could be marketed as first grade, the balance being sec- 

 ond grade. How much did he get for each lot, and how 

 much of the money was due to the spraying? 



385. The same farmer then began potato seed selec- 

 tion. It took him two days (20 hours), worth $4 of his 

 time, to select and to plant according to rules. But the 



