112 
Tlte Paris Sewage Irrigation at Gennevillicrs. 
to proceed from natural gravity. It is only under such circum- 
stances that a farmer can lend his fields to the process of irriga- 
tion, which may now be admitted to be the most effectual means 
that can be devised for disposing of town-sewage, without nui- 
sance to man or beast, and with great advantage to the produc- 
tion of food. 
This is a modern problem which has been forcibly raised in 
our times, in consequence of our better understanding of the 
hygienic economy of towns ; and its solution has become an 
absolute necessity. The excreta of civilised communities must 
be effectually removed from the precincts of human dwellings ; 
not, indeed, by relieving one spot, only more effectually to 
poison another, through a mere local transfer of the pestilence ; 
for this would only spread the nuisance 6ver an extended area, 
and under aggravated circumstances ; but by a process of 
absorption, based upon the natural principle of transformation 
of organic matter within the soil. In that powerful chemical 
laboratory of Nature, sewage is not only bereft of its noxious 
effluvium, within the influence of which neither animal nor 
vegetable life can exist, but the very pestilential elements 
which make it a rank poison are converted into succulent food. 
A knowledge of that well-known chemical property of soils, 
than which there is no more powerful deodorising and disinfect- 
ing agent in Nature, naturally suggested to the minds of those 
interested in the solution of the sewage problem, to spread the 
contents of town-sewers over lands conveniently situated, instead 
of wasting their fertilising treasures into watercourses, thereby 
polluting rivers, destroying animal life within their bosom and 
vegetable life on their banks, and, moreover, fouling all the 
adjacent country's atmosphere, to the serious detriment of the 
health of its inhabitants. 
It is not long since the metropolis of France has enjoyed 
the sanitary advantages of sewers, and even now the system is 
still incomplete as compared, for instance, with that of London, 
inasmuch as nine-tenths of the cesspool-drainage are still with- 
out any direct communication with the sewers. The remaining 
tenth only communicates with the sewers so far as the liquid 
offal is concerned, the solid being confined within vessels called 
tinettes, which, when full, are periodically removed in vehicles^ 
suited for that purpose, and replaced by empty ones. Thus 
the contents of nine-tenths of the Paris cesspools have to be 
periodically pumped up, and their contents removed to Bondy, 
where they undergo the process which converts them into jmi- 
drettc, or human guano. 
Tlie tinette system, however, has been applied to all the newly- 
built houses, and is gradually extending. It consists of an iron 
