FERTILIZERS. 63 



require in about the same proportions." Steamed bones, 

 burnt bones, bone-black, or char, cannot take the place of 

 the raw ground bone ; neither can any form of the German 

 potash salts take the place of the ashes : for animal matter 

 is needed in the bone, and potash in a caustic form in 

 the ashes, to produce the chemical action. Says Dr. 

 Nichols, " Five barrels of this mixture to the acre is a 

 cheap and most effective dressing for any kind of a crop." 

 The material used would cost, in Massachusetts, about 

 $7.50. I would advise using the mixture in the hill, with 

 about half the usual quantity of barn manure ploughed or 

 harrowed in. In my own practice I incline more and 

 more to keep the manure near the surface, that it may 

 have the advantage of all rains, to moisten and help dis- 

 solve the plant-food in it, for plants can take their food 

 only when in a liquid or gaseous state. With this end in 

 view, I surface manure for most crops, and work slightly 

 under with the wheel or some other good harrow. Mr. 

 Darling advises a little different method and proportions : 

 " Mix 5 barrels finely ground bone with 5 barrels of un- 

 leached hard-wood ashes ; add water sufficient to moisten 

 the mass, and then cover with loam. Leave the heap three 

 weeks, adding a little water if it, on examination, appears 

 to be nearly dry." Mr. Darling, who is well acquainted 

 with fertilizers, and might be presumed to know of what 

 he is speaking, says that the mass will be worth fifty dol- 

 lars per ton, which is at least double the cost of the mate- 

 rials that entered into the composition of the heap. 



When bones are steamed under pressure, to extract 

 from them oil and gelatine, they are left in such a state 

 that when ground, I have found, on using a lot of a dozen 

 tons that had stood in heaps some months after having 

 been steamed, apparently as good effect on crops as though 

 they had been treated with acid. I found, that, when used 



