v.] BONES AS A MANURE. 33 



were therefore used with great profit. It is easy to 

 understand why such good results followed their use. 

 These lands had been used for feeding cows for 

 many generations. Any herbage consumed by these 

 cows would be robbed of its phosphoric acid, 

 because the animal required a supply of phosphate 

 of lime for the formation of milk, and for the 

 growth of the young calf, and very little would be 

 returned to the soil in the excrements. If we ex- 

 amine the composition of milk we find that there is 

 i Ib. of phosphate of lime in about 25 or 30 gallons 

 of milk, and it may be fairly calculated that the annual 

 demand upon the land for each cow is equal to 80 

 Ibs. of bone. There was, therefore, a deficiency of 

 phosphate of lime consequent upon this long-continued 

 removal from the soil ; and when bone was supplied, 

 lands which had become almost valueless, suddenly 

 became rich and luxuriant. 



6 1. The use of bones was also extended to tillage 

 land, and with equally satisfactory results. Large de- 

 mands are made upon the soil for phosphoric acid 

 (41) by its continued removal in corn crops, and by 

 sheep and other live stock, and as these had caused a 

 deficiency upon ploughed lands, like that we have 

 already noticed upon the dairy pastures, similar bene- 

 fits were gained by the application of bones. The use 

 of bane thus became a settled practice, and was found 

 to be highly remunerative. 



62. The next step in the use of bone was its reduc- 

 tion to a fine condition, and it was in that form sold as 

 bone dust, for although it was by no means as fine as 

 dust, it received that name. The chief difference was 

 the additional labour of grinding it smaller, so as to 

 pass through a finer sieve, but the effect upon the land 

 was marked by its more rapid action. 



63. With a view of attaining still greater rapidity of 

 action bones were frequently "fermented." This was 

 accomplished by putting half-inch bones into a heap, 



