158 ESSAY ON TOP DRESSINGS 



brought from all parts of the world. Agents are employed in 

 this country to collect bones to enrich the farms of England. 

 It is to be hoped that every farmer will save a substance which 

 has been so long thrown away, and which would prove one of 

 the richest manures he could use. The bones, when dry, may 

 be crushed and pulverized with an axe. There are rainy days 

 enough which would not be better employed. Mills are es- 

 tablished in various parts of the country, for the purpose of 

 grinding bones. They are sometimes ground in plaster mills. 

 A mixture of crushed bones and ashes, or leached ashes, forms 

 one of the most valuable top dressings. Nor will this applica- 

 tion, in small quantities, be thought expensive, when we con- 

 sider that the animal part of bones, which amounts to about 

 one third, contains eight or ten times as much ammonia as the 

 ordure of the cov/, and that the fertilizing salts in bones are 

 sixty-six times the amount of a like quantity of the ordure of 

 the cow.* So that a smaller quantity of bone dust will ans- 

 wer the same purpose of a much larger quantity of manure 

 from the stable. We can but hope that every farmer will try 

 the experiment. It may be done on a small scale, at first, 

 though in the vicinity of every butcher's establishment, bones 

 can commonly be procured in any quantity. 



Thus far we have treated of manures which belong more 

 peculiarly on the siu'face, as a top dressing for grass. For 

 though they are sometimes used, especially plaster, on plough- 

 ed land, with potatoes and other crops, yet their influence on 

 the surface is thought to be far more effective. Indeed, the 

 benefit of lime, plaster, and charcoal, would, in a great meas- 

 TU'e, be lost were they to be buried to any depth in the earth. 

 But there are other manures which are often used as top dress- 

 ings. Little need be said of the comparative value of animal 

 substances. They have been artificially applied from the great- 

 est antiquity. They are mentioned by Homer, which distinct- 

 ly shows that their value was understood a thousand years be- 

 fore the Christian era. There is every reason to believe, more- 

 over, from other ancient authors, that great care was exercised 

 in preserving and applying manures to fertilize the earth. Nor 



* We state this on the authority of Dr. Dana. 



