66 CHEMISTRY, GEOLOGY 



feather dipped into strong vinegar, when the white 

 fumes will be apparent. The same result is 

 attained if quick-lime is mixed with sal-ammo- 

 niac : arid a similar result is caused if lime is 

 mixed with the liquid manures of the farm-yard. 



For turnips and potatoes, guano should be 

 mixed with an equal weight of the common farm- 

 yard manure ; because, alone, it does not contain 

 sufficient organic matter to maintain the land in 

 its most productive state. 



A fair proportion for grain and corn crops is 

 about two hundred weight to the acre as a top- 

 dressing ; and for potatoes or turnips about the 

 same quantity when mixed with half the amount 

 of common manure, or about three hundred 

 weight of the mixture, per acre. 



Where fish are abundant, they may be very 

 profitably used as a fertilizer. They are best 

 made into a compost with marl and earth, and 

 the heaps should be turned or worked over two 



Questions. Why should guano, for some crops, be 

 mixed with common manures ? How much guano to the 

 acre is needed for grain and corn crops ? How much when 

 mixed with an equal weight of common manure, for pota- 

 toes and turnips? Are fish useful as a manure? Ho"W 

 should they be prepared ? 



