64 CHEMISTRY, GEOLOGY 



Another great advantage of the tank is, that 

 during the spring and summer months its con- 

 tents, after fermentation, and diluted with once 

 or twice its bulk of water, may be applied, by 

 the watering-cart, to grass land, young clover, 

 or any other young crops. 



The ammoniacal liquor of the gas-works, 

 diluted with four or five times its bulk of water, 

 may be, where attainable, employed in the same 

 manner and for the same purposes as the liquid 

 manure of the farm-yard ; or, it may be made 

 into a compost with peat and vegetable mat- 

 ter. 



The excrement of birds is a most valuable 

 manure. The article now so popular, and known 

 as guano, is the excrement of sea-fowls, which 

 has been accumulating for ages in the localities 

 where it is found. Farmers should carefully 

 collect and preserve for use the dung of hen- 

 houses and pigeon-cotes ; they make a very effi- 

 cient top-dressing for young grain crops, and 

 may be used, wholly or in part, in place of the 



Questions. Has the tank any other advantage? To 

 what purposes may the ammoniacal liquor of gas-works be 

 applied ? What is guano ? Is the excrement of other birds 

 useful as a manure ? 



