85 
DEODORIZATION OF SEWAGE AND OTHER WATER BY IRON 
AND ITS OXIDES. 
In our last number we alluded to the use of the sesqui- 
chloride of iron for this purpose, as recommended to the 
Metropolitan Board of Works by Drs. Hoffman and Frank- 
land. 
When it is known that the estimated value of London 
sewage alone, as manure, is £3796 per diem, or £1,385,540 a 
year, surely some means should be devised to prevent this 
running away as waste matter; nay, worse than waste, since 
it is allowed to become prejudicial to health and life, and the 
river Thames is by it converted into a mere tidal ditch. 
Ordinarymetalliciron, it appears, also possesses theproperty 
of removing from water all organic impurities contained in it, 
causing their precipitation by contact; and filters are now 
being made of this metal for domestic use. 
We remember having drank water that had been kept for 
seven years in an iron tank, and it was perfectly fresh and 
good. 
M. Kiehlman has lately ascertained that the hydrated oxide 
of iron is a most effectual decoioriser, from the oxygen thereof 
being liberated and acting upon the colouring principle, 
thus causing its destruction by eremacausis or slow com¬ 
bustion. In the same way, he conjectures, the rotting of the 
wood in our ships, &c., is brought about by the use of 
iron nails, and that spontaneous combustion is effected by 
the same means, the oxide of iron being the communicator of 
oxygen to the inflammable materials. 
The Editor of the Chemical News, in which periodical M. 
Kiehlmaffs paper appears, has therefore supposed that the 
oxide of iron might be a valuable agent in the purification of 
water also. 
In a subsequent number of the same journal, Mr. J. Horsley 
states that he has found the peroxide of manganese, an in¬ 
valuable agent, both as a decoioriser and deodorant: and if a 
more powerful one were required, it would be found in a mix¬ 
ture of this, and the chloride of lime, in the proportion of three- 
fourths manganese and one-fourth lime, a compound which 
has cheapness to recommend it as well as efficacy. 
