492 
The Iiifluence of Lime on the 
valuable addition to peaty soils. Lime decomposes the remains 
of ancient rocks, containing- potash, soda, magnesia, &c., occurring 
in most soils ; it at the same time liberates silica from these rocks. 
It is consequently a means of tlie supply of most important 
mineral food for vegetation. Lastly, lime is one of the sub- 
stances found uniformly and in considerable fjuantity in the ashes 
of plants : it is a necessary part of the plant's structure, and if it 
is deficient in the soil its application may be beneficial simply 
as furnishing a material indispensable to the substance of a 
plant. Such are some of the explanations given in books of the 
action of lime on soils. 
No doubt they are good as far as they go, and any one of 
them would form a substantive cause for results even greater 
than those which are experienced from the use of this powerful 
auxiliary — supposing — that is to say — that our experience on the 
subject furnished only facts which could be explained upon one 
or other of these suppositions : such, however, is hardly the case. 
No doubt lime does a great deal of good to peaty soils, but so it 
does to land which is almost destitute of organic matter ; and 
indeed we may go further, and say that it is made in some cases 
to supply a real deficiency of sucli matter, as in the practice of 
the farmers in some parts of Wales, who will send 15 miles for 
a load of lime, but despise the stable manure, which they may 
have for the fetching within 2 miles of their doors. This may 
be said to be bad farming : very possibly it is ; but it is, per- 
haps, justified by the result, and Ave should bew;ne, in our transi- 
tion state from darkness to light, that Ave do not employ our 
newly-gotten knoAvledge to judge and condemn a practice, in- 
stead of accepting that practice as an addition to our stock of 
facts from Avhich, patiently and by sIoav degrees, Ave may deduce 
a philosophical system. This remark is, hoAvever, by the way, 
and applies to all reasoning on agricultural subjects; but it has 
always struck me, that until Ave have proved beyond all possi- 
bility of question that it is bad, Ave should entertain the greatest 
respect for any local practice of general adoption, no matter how 
opposed it may be to our preconceived notions. Men do not, 
as a rule, blindly folloAV each other's lead, and it Avill generally 
be found that there is at bottom some good reason for a practice 
which universally, or almost uniA'ersally, obtains in any district. 
To return, hoAvever, to lime. We find it applied Avith success 
equally on land rich in, and nearly devoid oi, organic matters. 
We find it effecting great good in soils already abounding in 
salts of lime.'^' Here, therefore, it cannot be as a source of lime for 
* On foils of the London clay, iu the neighbourhood of Farnham, lime is uni- 
formly applied with great success. This clay wlieii examined is found to contain 
