Half-a-dozen English Seicagc Farms. 
439 
I add one word more on the policy which Mr. Bailey Denton 
strongly urges of having somewhere on every sewage farm a suffi- 
cient area set apart expressly for intermittent downward filtration, 
" not to be considered and treated as intensified irrigation, as it 
has been called, but designed and carried into operation as a 
distinct work to be utilised at all times when it would prove the 
safetij valve to irrigation.' I quote these words from his paper 
read before a meeting on river purification, held at Edinburgh on 
the 16th of January, 1873.* His contention appears to be that 
this expedient will tend to make sewage more palatable to the 
farmer and more susceptible of profitable use by helping him 
under the difficulty — occasionally it is believed a costly diffi- 
culty — under which, of course, he is placed of having to deal with 
all the town sewage daily, whether he has crops fit for it or not. 
When none of his land is fit for turning sewage to profitable use, 
this intermittent filter will be ready in which to kill or destroy 
it ; and thus he will not be forced to apply it to his land at the 
risk of injury to it or to the crops it bears. 
It seems to me that Mr. Bailey Denton's proposition is espe- 
cially acceptable only in those cases where the land is not 
naturally sufficiently porous for easy filtration over the whole 
farm. In that case, unquestionably, it mav be desirable to select 
the most suitable plot for special equipment as an apparatus for 
merely oxidising and defaecating sewage. But where the whole 
of the land is pervious and suitable for the work of sewage de- 
faecation, to set apart a portion which may be loaded with the 
work more heavily than the rest seems to me like an attempt, if 
possible, to achieve a failure. For the power which the land, 
and the air within it, possesses of converting sewage into a 
non-putrescible liquid is, of course, limited, even under the most 
favourable circumstances ; and the work is more likely to be 
perfectly complete when the sewage is distributed over and 
throughout a large quantity than over and throughout a small 
quantity of aerated earth. It is, I submit, precisely the same 
process on which you depend for sewage defaecation whether you 
employ a drained and irrigated farm or a drained and irrigated 
filter-bed ; only the former, supposing it to be sufficiently porous 
and well drained, having less to do per acre, is more likely to do 
it thoroughly ; and, having a larger area on which a profitable 
crop may be at; the same time cultivated, it is the more likely 
to make a considerable contribution by its produce towards the 
repayment of the costs which have been incurred. 
* Edinburgh : Edmonston and Douglas. 
2 G 2 
