10 



Present State of the Science of 



There is another class, however, of manures which deserves 

 inquiry as much as any branch of agricultural practice, and which 

 also seems to lend itself more readily to our experiments, — those 

 which are not produced by animals upon the farm, whether in the 

 yard, the stall, or the fold, but which are procured by the farmer, 

 either from the earth, lime, for instance, marl, peat- ashes, gypsum, 

 nitre ; or, as the refuse of certain trades, such as bones, rape- 

 dust, malt-dust, even woollen rags. The former of these, which 

 may be called the mineral manures, are now perhaps in more 

 limited use than in past times; still, in Devonshire and some 

 midland counties, lime is regarded as indispensable, and is car- 

 ried very long distances over bad roads at a heavy expense; but 

 marl, which was once so highly valued, is in many districts almost 

 forgotten. Not so with the second class, which may be called the 

 refuse manures : of these, bones in particular form a new feature 

 in our husbandry, and their consumption is yearly increasing. In 

 the year 1823 the declared value of all the bones imported from 

 foreign parts was but 14,395Z. ; in 1832 it was 78,000/. ; in 1835 

 it had reached 155,279/. ; in the next year, 1836, it advanced to 

 171,806?. ; and in the following year, the last of which we have 

 any account, it amounted to no less a sum than 254,600/. This 

 is the declared value, which the real value greatly exceeds ; and 

 it excludes altogether, of course, the large quantity of this article 

 which must be produced at home. At present, bones are chiefly 

 applied to the turnip-crop, and on some soils their effect is 

 certain and great. Yet no single instance can show the neces- 

 sity and advantage of scientific inquiry more than this new 

 manure. It is well known that bones contain a large portion 

 of oil, which is usually extracted by boiling ; and it might 

 naturally be supposed, since oily substances are used separately 

 as manures, that the natural oil should at least be left in the 

 bones, which are intended to be so applied ; and farmers, accord- 

 ingly, who purchase bones have complained that these had fraudu- 

 lently been boiled. Now, contrary to expectation, there is reason 

 to doubt whether the bones are not actually improved as a ma- 

 nure by the loss of that oil, by which, if such be the truth, their 

 own active principle, whatever it be, would appear to be deadened 

 and sheathed. This is a point that may be easily tested ; but 

 there are larger questions connected with the use of bones. They 

 are, as is well known, an expensive manure, and their price is 

 rising ; but it is by no means known in what quantity they should 

 be applied. At 10 bushels to the acre, however, if the cost be 

 3.9. per bushel, the outlay is already large, namely 30s., a sum 

 probably exceeding the rent. At 20 bushels it will be 3/., or 

 300Z. for a field of 100 acres. But as yet there is reason to doubt 

 whether any increased quantity beyond 25 bushels of small bones 



