208 BONES. 



is perceived from coarsely levigated bones, while 

 bone-dust finely powdered operates energetically. 

 During the putrefaction of the gelatine, the bone- 

 earth also becomes gradually soluble and fit for the 

 nourishment of plants ; the more rapid, therefore, 

 the progress of decomposition in the earth, the sooner 

 do both these constituents — the organic as well as 

 the inorganic — develop their activity, and the more 

 will their principal operation take effect during the 

 first and second years, — an advantage that will be 

 duly appreciated by the farmer. 



From these facts, the result of many practical ex- 

 periments in Saxony — that hone-dust on soils of 

 moderately binding quality^ and when used for autumn 

 sowings is of far more certain and advantageous 

 action than upon very heavy or very light lands^ and 

 ivhen used for summer crops — receives an obvious 

 explanation. In very binding and damp soils, air 

 is wanting, in very loose land, water; both these 

 elements, air and water, must be present, if the 

 decomposition and dissolution of this manuring 

 agent are not to stand still. There are districts in 

 Saxony where bone-dust produces no observable 

 effect whatever, while guano works excellently, and 

 where, indeed, the former, even when dissolved by 

 sulphuric acid, shows no trace of operation till the 

 second or third year. Whether, in addition to the 

 physical condition of the soil, its chemical consti- 

 tution also contributes to bring about this result, can 

 only be decided by continued practical experiments, 



