484 
of hornbeam, and 4°5 in the ashes of the bark of 
hornbeam. These proportions forcibly show how 
indispensable the phosphate of lime is to the 
health and growth of the most useful plants of 
both the farm and the forest, and, in consequence, 
how mighty an influence is exerted upon them 
by bone-manure. ‘Turnips, potatoes, and white 
clover, too, though not named in our list of spe- 
cial plants, are so powerfully affected by the 
presence of phosphate of lime in the soil as to be 
mainly dependent on it for their vigour and lux- 
uriance. White clover, when well stimulated by 
bone-manure, grows with such energy as to take 
almost entire possession of the soil, or to dwarf 
and exterminate the coarse kinds of herbage; 
and, when first grown upon boned ground in 
England, was foolishly, though not very naturally, 
supposed by some farmers to derive its very seeds 
from the bone-manure, so that, as they imagined, 
it did not require to be sown. The seeds of this 
plant, not only contain a large proportion of 
phosphate of lime, but possess extraordinary 
longevity, and are most extensively though dor- 
| mantly diffused in almost all kinds of soils and 
situations in England ; so that whenever they 
are brought within the reach of aeration, and 
subjected to the manurial action of phosphates, 
they germinate and grow with surprising vigour. 
-White clover has sprung up after a conflagration 
in a large town, simply because the action of the 
heat occasioned aeration of the ground, and the 
incineration of the wood set free upon the soil a 
comparatively large proportion of phosphate of 
lime; and, for similar reasons, it has sprung up 
as if by magic, and flourished with almost super- 
natural luxuriance, in fields which have been 
suddenly phosphatized by the introduction of 
bone-manure. ‘The highly fertilizing power of 
phosphate of lime, also, affords a main explana- 
tion of the fact that bones are beneficial nearly 
in the ratio of the porosity of the soil, and are 
almost totally useless in wet, tenacious clays; for 
this salt, as it exists in bones, is always slow of 
liberation, and can in any case be set free only 
under the action of the air; and hence it is 
readily evolved in soils which possess a full and 
rapid aeration, and remains perfectly fixed and 
stubborn in soils which lock it up from atmo- 
spheric influence. 
But another powerful method in which crushed 
bones exert a fertilizing power, consists in their 
extraordinary capacity for absorbing and retain- 
ing moisture. When any vigorous plant upon a 
boned field is pulled up, it will generally bring 
up small pieces of bones with its roots; and 
when it is minutely examined, it will be seen to 
have grasped the little pieces and pervaded their 
cavities with its radical fibres, while these cavi- 
ties will be seen to be clammy or even copious 
with the liquid nourishment on which the spon- 
gioles were feeding. The very contact which the 
radical fibres of young turnips obtain with bone- 
manure, and which they cannot, in any of the 
BONE-MANURE. 
ordinary methods of application, obtain with 
farm-yard dung, has been assigned by some in- 
telligent farmers as the sole reason of the para- 
mount power of bones over the turnip crop.— 
“Contact with manure,” says a writer in the 41st 
number of the Quarterly Journal of Agriculture, 
“will cause turnip-seed to vegetate in a short 
time. Could the seed have been placed in con- 
tact with farm-yard manure as easily as with 
bone-dust, the latter would never have acquired 
the fame it has as a turnip manure. The firm- 
ness with which the roots of the turnip grasp 
the manure, shows the great capacity for manure 
which they possess in the early stage of their 
growth. It is this tenacity for manure of the 
root-fibres which raises so much of the bone-dust 
to the surface of the ground, by adhering to the 
roots of the ejected plants; for it is found, in 
singling the turnip crop it is liable to be brought 
up to the surface of the ground, by the root-fibres 
of the ejected plants ; and whenever turnip-seed 
vegetates in contact with farm-yard manure, the 
same inconvenience results.” The plentiful supply 
of moisture for turnips which bone-manure at- 
tracts and maintains in open and comparatively 
arid soils, affords another though but secondary | 
explanation of its specially beneficial action upon | 
light and porous land; and the repulsive power | 
which fatty matter exerts against moisture, fully 
explains the apparent superiority of boiled bones 
to unboiled ones in fertilizing effect upon the 
turnip crop. 
Another source of the manurial power of bones, 
though applicable, not to the turnip crop, but to 
the succeeding crops of the rotation, is their 
gelatine and their fat. Both of these substances 
consist of elements which enter very largely into 
the organic substance of all plants; so that, 
throughout the whole process of their decom- 
position on the soil, they resolve themselves into 
direct and perfectly prepared food for the grow- 
ing crops. The more the bones have been fer- 
mented, too, the more soluble is their gelatine, 
and the more prepared for assimilation is their 
fatty matter ; and hence the high advantage of 
working unboiled bones into fermented composts, 
or mixing them with foreign substances fitted to 
promote their fermentation. Yet as the presence 
of oil and gelatine resists the attraction of mois- 
ture, retards the development of the manurial 
power upon turnips, and constitutes a kind of 
manurial agency similar to that of the most com- 
mon fertilizers, and not at all of the specific and 
mighty nature of the phosphate of lime, a very 
serious question arises whether more profit might 
not accrue to the farm from extracting the oil 
and the gelatine from all unboiled bone-manure, 
and applying them to other uses. “ By compar- 
ing all the facts,” says one writer, “ we naturally 
come to the conclusion, that the most economi- 
cal use of bones is to extract from them the oil 
and gelatine, which, if not of sufficient value for 
the manufacture of glue or of ammonia, may be 
