Miscellaneous Fertilizing Materials 111 



they are not used in too large quantities, no serious injury 

 is liable to follow. In fact, salt in some instances is a 

 substance of considerable indirect manurial value. Sea- 

 weed manure is certainly worthy of consideration where it 

 can be obtained in quantity for the expense of carting. 



Wood-ashes and tanbark-ashes. 



Wood-ashes contain potash in one of the best forms, 

 and were, in the early history of manuring, practically 

 the only semi-artificial source of this element. At the 

 present time, however, the supply is limited, and the aver- 

 age content of potash in the commercial article is much 

 lower than was formerly the case. 



The pure ash is not a uniform product. That from the 

 different varieties of wood varies in composition. As a 

 rule, the softer woods are poorer and the hard woods richer 

 in potash than the average, the range being from 16 to 

 40 per cent. 



Ashes also contain lime in large quantities, while phos- 

 phoric acid is contained in much smaller quantities. 

 Wood-ashes, as usually gathered for market, however, 

 contain very considerable proportions of moisture, dirt, 

 and the like, which cause a variability in composition 

 not due to the character of the woods from which they 

 are derived. The average analysis of commercial wood- 

 ashes shows them to contain less than 6 per cent of potash, 

 2 of phosphoric acid and 32 per cent of lime. Leached 

 wood-ashes contain on the average 30 per cent of moisture, 

 1.10 of potash, 1.50 of phosphoric acid and 29 per cent 

 of lime and 2 to 5 per cent of magnesium oxide. 



Ashes are probably one of the best sources of potash 

 that we have, so far as its form and combination are con- 

 cerned, being in a very fine state of division, and in such 



