APPLICATION OF ASHES AS A MANURE. 273 



such, for instance, as the residue left in preparation of 

 potash, possesses for many fields a high value as a 

 manuring agent, not only on account of the potash 

 always present in it, but also of the phosphate of lime 

 and soluble silicic acid it contains. 



As the upper layers of our corn-fields contain already 

 naturally an excess of potash, in proportion to the other 

 food elements, ash-manuring, when confined to the sur- 

 face soil, rarely exercises a lasting effect ; but where the 

 ash is carried down to the proper depth, it affords an 

 excellent means of obtaining permanent crops of clover, 

 turnips, or even potatoes. Intelligent manufacturers 

 of beetroot sugar use with great success the residuary 

 matter from the distillation of their molasses, which 

 contains all the potash-salts of the beetroot, for manur- 

 ing their fields, to restore to them the potash removed 

 in the beetroot-crops. 



12* 



