On Paring and Burning. 23 



2. The ashes contain, as will be seen, a -large proportion of 

 potash in a soluble condition, as well as of chloride of sodium ; 

 and as alkalies are very beneficial to green crops, the presence 

 of alkalies, especially that of potash, no doubt accounts in part 

 for the benefits resulting from the application of red vegetable 

 ashes to root-crops. 



2. The insoluble silicious matter consists chiefly of burnt clay, 

 and contains a good deal of potash in a state in which it is not 

 at once soluble in water. But as burnt clay is more readily 

 penetrated by atmospheric air, there can be no doubt that the in- 

 soluble potash contained in it will be rendered soluble and made 

 available for the use of plants much more readily than it is from 

 unburrit clay. 



I have just stated that the total amount of perfectly dry ashes 

 per acre was ascertained to be 11 tons 11 cwt. 2 qrs. 11 Ibs. 

 100 parts of these ashes contained *71 of phosphoric acid. 



This percentage, calculated for the total produce in ashes, 

 gives 184 Ibs. of phosphoric acid ; 184 Ibs. of phosphoric acid, 

 united with lime, give 398 Ibs. of tribasic phosphate of lime or 

 bone-earth per acre. 



Commercial bone-dust, I find, contains, on an average, 46 per 

 cent, of bone-earth. 398 Ibs. of bone-earth, accordingly, are 

 equivalent to the phosphate of lime contained in 7 cwt. 2 qrs. 25 Ibs. 

 of commercial bone-dust. 



The weight of a bushel of bone dust varies from 40 to 

 44 Ibs. Taking 43 Ibs. as the average weight per bushel, 

 7 cwt. 2 qrs. 26 Ibs. of bone-dust will give almost exactly 

 20 bushels. 



Thus the ashes from this field contained a quantity of phosphoric 

 acid which is equal to that contained in 20 bushels of bone-dust. 



This is an important fact, and affords the explanation why 

 vegetable ashes are so beneficial to turnips, and why better crops 

 of roots are obtained on the thin brashy soils of the Cotswold 

 hills, by paring and burning, than with the use of any amount of 

 farmyard manure or any description and quantity of artificial 

 manure. Many Cotswold hill farmers are not 4 a little proud of 

 growing good roots on poor thin soils without manure. I once 

 heard a farmer in our neighbourhood quite exult in the idea that 

 he never used a single bushel of bone-dust for his turnips, and 

 had not the least confidence in phosphates, or would ever think 

 of using superphosphate, or any other new-fangled manure, for 

 his roots. But are red ashes no manure ? In point of fact, the 

 land, in the case before us, received a heavier dressing of essen- 

 tially valuable fertilizing constituents in these ashes than it 

 would be likely to receive in any other description of manure, 



