On the Fliusplioric Strata nf the Chalk Formation. 57 
It will be remembered that nearly two-thirds of the wei<rht of 
recent bones is earthy matter, principally pliosphate and carbonate 
of lime ; the other one-tliird consists of a peculiar animal sub- 
stance called (jclatiue, some oil or fat, and a variable quantity of 
moisture. For all practical jjuiposes the phosjihate of lime may 
be taken to average 50 per cent., or one-half, of the fresh bone. 
Experience and science are equally decisive in attributing to 
the animal matter of bones a very important share in manurmg 
efficacy ; and whatever fluctuations may have occurred in the 
progress of opinion on tliis head, the abiding conviction in the 
minds of agricultural authorities at the present time is, that the 
animal matter of bones, like all other substances rich in nitrogen, 
is of very high value as a fertilizing agent. 
But whilst a full share of importance is attached to the animal 
portion of bones, the effects which follow their application are 
far greater than could in the most favourable opinion be ascribed 
to the sole agency of this ingredient; and direct experiments are 
not wanting to prove that, when purposely se])arated from the 
earthy portion, tlie gelatine is incapable of influencing vegelation 
in a degree at all comparable with that which is exhibited by 
the compound manure.* On the other hand, the earthy portion 
has been employed in every variety of form with the most maiked 
results, and trustworthy experiments (more especially those of 
Mr. Hannam and Mr. Lavves) have placed beyond all doubt the 
beneficial effect of burnt bones on the turnip crop. 
Mr. Lavves, indeed, entertains the conviction that phosphate 
of lime exercises some special agency, apart from the mere supply 
of a necessary ingredient of the structure of the plant ; but be 
this as it may, there is abundant evidence of the high powers, as 
a manure, of the phosphate of lime in bones. Of another kind, 
but not less striking, is the evidence derived from the analyses of 
plants, and of the soil in which they grow. In all the plants or 
parts of plants which are of any great nutritive value, ph()sj)hate 
of lime or some other compound of jihosphoric acid is alwavs to 
be found in large quantity, whilst the proportion in which it 
occurs is for the same plant so uniform as to preclude all question 
that it is essential to their very existence. When therefore, on 
the other hand, we are sometimes unable, with the aid of the most 
refined processes of analytical chemistry, to detect more than the 
merest traces of phosphoric acid in a soil, shall we not be justified 
in concluding that, properly applied, the compounds of this acid 
must be beneficial to the growth of crops on such a soil ? 
The attention of men of science and of agriculturists has from 
* See Mr. Hannam's Experiments, in the 6th volume of tliis Journal, 
part i. 
