MANURE. 187 



stronger than 100 lbs. of fresh cow-dung. Connected with 

 flocks and wool, there is a very valuable product, rich in all 

 the elements of manure, which is often lost or not used for 

 agricultural purposes, namely, the sweat, or natural soap of 

 wool. Fresh clipped wool loses from 35 to 45 per cent, of 

 its weight by washing. This is due to a peculiar matter 

 exuded from the wool, and which consists chiefly of potash, 

 lime, and magnesia, united to a peculiar animal oil, forming 

 an imperfect soap. It is remarkable that this soap of lime, 

 in all other cases insoluble, is here soluble in water. The 

 experience of the best French agriculturalists, is full of tes- 

 timony to the good eff*ects of this wool sweat. It has been 

 calculated that the washings from wool, annually consumed 

 in France, are equal to manuring 370,000 acres of land. 



223. Bones consist of variable proportions of cartilage, 

 bone earth, and carbonate of lime. The bone earth may be 

 estimated at one-half the weight. It is a peculiar phosphate 

 of lime, containing 3 parts of lime to 1 of phosphoric acid. 

 A great part of the value of bone as manure, depends on its 

 cartilage. The animal part of bones being one-third of their 

 weight, the ammonia is equal to 8 or 10 times that of cow- 

 dung, while, if we regard the salts only, 100 lbs. of bone- 

 dust contain nearly 60 times as much as an e'qual weight of 

 cow-dung. Such statements while they express the chemical 

 facts, are almost, if not quite, supported by the testimony of 

 those who have, in practical agriculture, applied these con- 

 centrated animal manures. It is a common opinion, that 

 bones from the soap-boiler have lost a large portion of their 

 animal matter. It is erroneous. Boiling, except under high 

 pressure, extracts very little of the gelatine, and not all the 

 fat and marrow. Heads and shoulder-blades and the smaller 

 bones still contain, after boiling, 3^ per cent, of fat and tal- 

 low. If the phosphate of lime of such bones is dissolved 



