ANIMAL MANURES. 1 35 



would lead us to suppose, are capable of contributing to the 

 j^rowth of plants ; and, in the present state of our knowledge, 

 and before we are warranted by experiments made on the 

 •ils — not of Germany, England, or Scotland, but of those 

 iormed from our Irish rocks, and under the influence of our 

 Irish climate — I would, I repeat, not advise the farmer to 

 follow the opinion of those who would direct him to bum 

 bones before applying them to his fields. It would, I con- 

 ceive, be almost as judicious for him to bmn Patagonian 

 guano, to procure the phosphates which give that substance 

 its chief value. (1 85) 



200. To what crops should bones be applied? — Popular 

 opinion, and th^ practice of the most experienced farmers, 

 have pointed them out as specially/ adapted for the turnip- 

 crop. Like guano (191), bones contain all the ingredients 

 which plants require for their growth; but their analysis 

 (197) shows us that some of the inorganic matters are not 

 present in sufficient quantity to render it safe for the farmer 

 to rely upon them as the only manure for his fields for a 

 number of years. When the soil is deficient in alkalies, if 

 you grow upon it a crop of turnips, 20 tons of which, in the 

 tops and bulbs, carry away so much as 265 J lbs. of potash 

 and soda, its fertility will be seriously impaired, if no other 

 manure than bones be used ; hence it is advisable that the 

 farmer should combine with them farm-yard dung, common 

 salt, kelp, or some other manure capable of supplying these 

 substances. 



201. What is the difference in the action of bones and guano ? 

 — This is a frequent question. Like bones, guano can be se- 

 parated, by burning, into two parts — an organic combustible 

 portion, which is consumed, and a fixed, incombustible ash. 

 This ash usually contains the same ingredients that we dis- 

 cover in bone earth; but, in the different kinds of guano, 

 they ai'e found in very unlike proportions. The proportions 

 of organic matter and ash also differ very much in the dif- 

 ferent varieties of that substance which are brought to this 

 country: thus, in the genuine Peruvian, the organic matters, 



ipable of yielding ammonia, range from 50 to 60 per cent, 

 and the phosphates of lime and magnesia average about 26 

 per cent ; while in the Patagonian, and some other varieties, 

 the relative proportion of these substances is very different, 

 and approximates them to bones in their composition. But 



