442 
Farming of Cormcall. 
of the gr.mite, diallage, and greenstone rocks is partly owing to 
the presence of iron — the proto-oxide becoming a peroxide. The 
red and variegated colours of our slates (14) are owing to the pro- 
portion of iron contained in them. 
66. The organic Elemmts of Plants. — According to Boussin- 
gault and other French authorities, the relative efficacy of all 
manures depends upon the proportions of nitrogen they severally 
contain — the farmer's principal source for which is farm-yard 
manure — consisting of the mixed droppings and litter of cattle, 
6cc. ; a large portion of the carbonaceous matters, too, is derived 
from the same source, which contributes its aid in increasing the 
produce of the soil by supplying a portion of the necessary food 
of plants. There \s, we are sorry to say, no department of 
Cornish farming in which greater negligence is exhibited than in 
the jireservation of mr.nures. The farmers appear not to under- 
stand the simple fact, that all the better part of their manures — the 
liquid portions — will either run away or fly away. The first are 
seen in the fluids that drain from the dung-hills into the water- 
courses; — and the second may be detected by the sense of smell 
— the offensive exhalations of the manure heaps being the nitro- 
genised substances flying away into the air, and at the same time 
tainting it v.ith effluvia. All animal and vegetable matters, or the 
remains of such, whatever purposes they may have served, or how- 
ever valueless they may be esteemed, are fertilizers in some degree, 
if properly applied to the soil, and are in fact the manures which 
are suffered to run to waste more or less in almost every farm-yard 
in the county.* 
* Many scientific gentlemen have endeavoured to enforce the necessity 
of the preservation of manures on the Cornish farmers, and amoni^ them 
we ought not to omit the exertions of Mr. Prideaux, an analytical chemist, 
who has repeatedly brought the subject before them. The following 
analyses of guano and of the solid matters of urine by this gentleman 
will show the farmers the necessity and the value of preserving the raw 
inatcriul of guano in their own farm-yards : — 
Abridged .Analysis of Guano. 
Guano. 
Solid Matters of Urin^e. 
No. 
1. 
No. 2. 
No. 3. 
liuman . 
Cow's. 
Mixed. 
Ammoiiiacal salts, organic nialttrs . 
62 
3 
C6-2 
44-C 
790 
70-0 
•75 
Phosphates 
23 
7 
29-2 
41-2 
8-0 
2-3 
•5 
9 
3 
4-6 
14-2 
12-9 
27-7 
•20 
4 
7 
Mostly Potass. 
These analyses are abridged from analyses of good samples, the con- 
densed statement of their composition giving a more practical view of it 
than the detailed analyses. It should be observed that alkaline sulphates 
