452 PHOS/PATE OF LIME YEARLY CARRIED OFF. 



effect. I have already shown that this prolonged action is not conclu- 

 eivc upon the point — since the organic matter lingers long, ev^n in buri- 

 ed bones — but a consideration of the necessary effect of long continu- 

 ed pasturage upon soils to which nothing is artificially added, lends a 

 singular support to the view that the bone-earth may act an important 

 and beneficial part upon old meadow and other grass lands. Take 

 the instance of a dairy farm in the neighborhood of a large town, — 



1°. The milk is all carried off the farm, either directly or in the shape 

 of butter; cheese, &c., and every 40 gallons of milk contain 1 lb. of 

 bone-earth, besides other phosphates. Estimate the average yield of a 

 good cow at JOOO quarts, or 750 gallons a-year, its milk will contain 19 

 lbs. of earthy phosphate — as much as is present in 30 lbs. of bone-dust. 



2^. Again, the urine of a milk cow, taken at 700 gallons a-year, 

 contains about 11 lbs. of the same phosphate. (A cow, not in milk, 

 gives on an average about 1300 gallons of urme — see page 460.) 

 Suppose only a third of this to run to waste, and the farm will lost for 

 every cow in this way about 4 lbs. — equal to about 6 lbs. of bone-dust. 



3°. But for every cow an annual calf is reared and sold off. Let this 

 calf contain but 20 lbs. of bone — then, for every cow it maintains^ a dairy 

 farm will lose of earthy phosphates upon the whole as much as, is 

 contained in 56 lbs. of bo?ie-dust. Suppose a farm to be pastured 

 for centuries, as those of Cheshire have been, and the produce to be 

 carried off in the form of milk, butter, and veal — we may reasonably 

 suppose that it will at length begin to feel the want of those phos- 

 phates which year by year have been drawn from its surface. It is 

 reasonable also to suppose that the addition of these deficient phos- 

 phates would impart new vigor to the soil, would cause new grasses 

 to sprout, and a more milk-yielding herbage to spring up. 



Such is the reasoning upon which I some years ago attempted to 

 found an explanation of the singularly striking effects produced by bone- 

 dust on the grass lands of Cheshire, while it failed materially to im- 

 prove those of other districts on which it had been tried. I still consider 

 it as by no means without its weight, though I cannot concur with the 

 extreme views which some have since adopted — that either in the case 

 of Cheshire, or in any other case with which I am acquainted, the benefi- 

 cial action of bone-dust is to be ascribed solely to its earthy constituents. 



§ Q. Of animal charcoal the refuse of the sugar refineries^ and 

 animalized carbon. 



1°. Animal charcoal, (bone black.) — When bones are charred or 

 distilled at a red heat in close vessels, they leave behind a coaly re- 

 siduum to which the name of animi' :iharcoal is usually given. By 

 this calcination the animal matter is almost entirely decomposed. 

 The charcoal still retains, however, a little nitrogen, and though it is 

 seldom employed as a manure, yet it is not wholly without effect m 

 promoting the growth of our cultivated crops. Thus in 1842, when 

 applied to Swedish turnips, Mr. Fleming obtained from the unma- 

 mired soil 12 tons 5 cwt. per acre ; but when manured with .10 cwt. 

 of animal charcoal, 21 tons 2 cwt. (see Appendix, No. VIII.) 



2*^. Refuse charcoal of the sugar refiners. — The animal charcoal 

 ;J»OYe described is c 3 afly employed for the purpose of removing the 



