164 MANURES. 



against many insects, when used in its fresh state ; 

 but in this state it should be very cautiously ap- 

 plied. 



The refuse liquor of gas works contains enough 

 ammonia to make it a valuable manure. It should 

 be filtered through earth or muck, which will retain 

 its valuable parts, and will be enriched by them. 



The refuse ley of soap factories and bleaching es- 

 tablishments contains greater or less quantities of 

 soluble silicates and alkalies (especially soda and pot- 

 ash,) and is a good addition to the tank of the com- 

 post heap, or it may be used directly as a liquid 

 application to the soil, or, better, filtered as above 

 described. The soapers' ley, especially, will be found 

 a good manure for lands on which grain lodges. 



Much of the benefit of this manure arises from the 

 soluble silicates it contains, while its nitrogenous 

 matter obtained from those parts of the fatty matters 

 which cannot be converted into soap, and conse- 

 quently remain in this solution, forms a valuable 

 addition. Heaps of soil saturated with this liquid 

 in autumn, and subjected to the freezings of winter, 

 form an admirable manure for spring use. 



IRRIGATION. 



Irrigation, strictly speaking, should not be con- 

 sidered under the head of earthy manures alone, as it 



