Seivage-Farming. 
391 
deal in considering it from a sanitary or an agricultural point 
of view. 
He would be a bold man indeed who maintained that by 
any management we could at present obtain the full value of 
the substances to which I refer ; but though it may be useless to 
indulge in hopes of the realization of such an amount, it is plain 
that, with our growing population and stationary acreage, it is 
our duty to let no means slip of increasing the productions 
of our fields. The most trustworthy estimates place upon the 
excreta of the people of these islands a value of not less than 
twelve millions sterling annually ; but as this part of the subject 
has received full discussion in the pages of this Journal at the 
hands of able scientific writers in previous years, I will only add 
that this sum is based upon the figures of Messrs. Lawes and 
Gilbert, who have placed upon the manurial ingredients of a 
mixed population an average value of 8s. Ad. per head per 
annum. 
A little consideration will show why the whole of this value 
can hardly be expected to be secured. In the first place, the 
collection of excrement can only be made profitable where large 
quantities of it exist ; and in the second, the necessary processes 
for carrying it away add enormously to its bulk without in any 
corresponding degree increasing its value. 
The conditions under which the elements contained in 
manures can be successfully applied to the soil are the subject 
of the most careful consideration to the farmer ; and although it 
is perfectly true that 8s. Ad. per head represents the intrinsic value 
of certain ingredients in sewage, the manner of its application 
may reduce such a sum to one-half or one-fourth in its result 
to the agriculturist. In the same way, the mode of application 
of certain manures may double their real value to the farmer. 
They come to him in a convenient, handy, and portable form ; 
they fill up a deficiency which practice tells him to exist ; he is 
able to apply as much or as little as he chooses ; and, in fact, 
he only finds them beneficial to certain crops and at certain 
stages of their growth. He does not forget, moreover, that the 
same value put upon the ingredients of well-made farmyard- 
dung would place it at a price which (notwithstanding all 
the esteem in Avhich that valuable fertilizer is held) no one has 
yet consented to pay for it. 
In a certain sense " the value of a thing is just as much as it 
will bring," and the worth of sewage under all the varying 
circumstances of its application can be determined by experience 
alone. Proof has yet to be afforded that under any conditions 
its intrinsic value, plus the cost of laying on, can be recovered 
Irom its use. It is certain, however, that more has been done 
