BOTANICAL SOCIETY OF LONDON. 283 
them out for the sustenance of the plants placed under its influence. 
No better agent could be found for improving the sanatory condition 
emanated from such matter, would be got rid of. According to a cal- 
eulation he had made, the matter so produced by a family of six would, 
in the course of a year, if subjected to the influence of this agent, yield 
£30 per annum ; und supposing the cost of the charcoal, and other ex- 
penses, to amount to £15, which they could not éxceed, there would 
still be a clear profit of £15 yearly. That might be doubted; but it 
Was a fact which he had ascertained after the most careful consideration ; 
and he had further ascertained, that were all the houses in London, which 
Were rented at upwards of £10, to adopt that system, they would earn 
à profit of £15 per house, or three millions of money per annum. In 
order to effect that, they would have to collect the refuse from all these 
houses into one great cesspool, and then apply the agent in question. 
Were this done, it would be the best means of clearing the metropolis 
-of that nuisance which now so much affects the health of its inhabit- 
ants; for, as matters now are, who could stand for an instant in the 
Vicinity of one of those gratings in the street, without being sensibly 
affected by the effluvia which proceeded from it P—After some illustra- 
tions in proof of his statements, Mr. Rogers concluded by stating 
that he was about to give the public a proof of the truth of his 
theory by erecting an establishment for the purpose of carrying it out. 
He did not see the smallest difficulty in effecting it in the metropolis. 
At the present time ashes were collected from the houses for the 
benefit of the parish; and why should the inhabitants not give up 
the other refuse matter to the parish, upon a proper understanding ? 
It was true no experiment had been as yet made on a large scale 
to test the truth of his theory; but the reason was, that charcoal 
could not be obtained on a large scale. He had been requested by 
the Guardians of the Poor at Macclesfield, some weeks ago, to try the 
experiment on a nuisance there; and although the charcoal was of a 
very inferior description, the peat having been obtained from a neigh- 
bouring morass, it had been eminently successful, and he had no doubt 
would be so in every case. 
202 
