308 WOOL — RAGS — OIL. 



refuse of glue manufactories, and similar matters, 

 form valuable manures ; because, though they do not 

 decompose so rapidly as other animal manures, they 

 slowly and gradually decompose, and continue to give 

 out ammonia, &c., for a very long time. 



821. The substances of this sort employed as 

 manures are very numerous; including as they do the 

 refuse of all those processes of the arts in which 

 animal matters are used, their value in all cases 

 chiefly depends on their slowly decomposing, and 

 affording a continual source of ammonia, &c. 



822. Although oil or fat of all kinds contains no 

 nitrogen, and therefore exhibits very little tendency 

 to change when pure, yet when mixed with earth, the 

 large surface which is exposed to the air assists in its 

 decomposition, particularly if other animal matters 

 also are present; and it accordingly forms a valuable 

 constituent of mixed manures. 



823. The dregs of oil, waste blubber, and refuse 

 oils of all sorts, are excellent manures ; soap, likewise, 

 in which oil or fat is combined with alkali, is used 

 with advantage whenever it can be obtained at a 

 moderate price. The waste soap of the wool factories 

 has already b^en mentioned as of great value (816). 



824. The water which runs to waste from many 

 manufactories in which soap is employed might be 

 used with great advantage for manure; it often holds 

 in solution a considerable quantity of valuable matter, 

 and might be well employed in the formation of 

 liquid manure. y^^'^'^^ 



