182 kiMMERIDGE SHALE. 



It should be taken into consideration that animal-charcoal con- 

 tains only 10 per cent, of carbon, Sanitary Carbon contains, as 

 shown in Dr. lire's Dictionary, 72 8 per cent., and by M. Duqnesne 

 48"l2 per cent, of carbon, and 21*84 per cent, of other allied 

 filtering media, or a total of 70'06 per cent. 



The efficacy of this mateiial, when applied to the purification of 

 sewage, has been conclusively demonstrated, not only by experi- 

 ments, but also by actual practical use. 



Among the experiments may be mentioned one conducted by 

 the proprietors, when a mixture of raw London sewage, drainage 

 waters from Cornish tin, iron, and clay-mines, and indigo, cerise, 

 green, and purple dyes, was filtered through the sanitary carbon, 

 and at the present time, some three years after the experiment, 

 the purified liquid is quite transparent and bright ; and another 

 by H. C. Bartlett, Esq., Ph.D., F.C.S., who says :— " The 

 decolorising power of this Char is very conspicuous in removing 

 the colouring matter of almost every dye including every present 



solution of the aniline dyes I have now a sample 



of urinous slops which was taken more than two months back in a 

 condition of putrid decomposition. It was filtered once through a 

 small quantity of the sanitary carbon, by which means all putres- 

 cent smell was immediately removed, and since then, although 

 exposed to a temperature at which decomposition is most active, 

 no further decomposition has taken place and the sample remains 

 entirely free from smell." 



To this purpose of filtration of sewage water, the sanitary carbon 

 is exactly suited ; it combines properties not met with in any other 

 filtering medium, arrests mechanically any objectionable matters 

 held in suspension, and chemically retains within itself the valuable 

 products which have hitherto been allowed to run to waste, to the 

 pollution of the rivers and watercourses of the country, and the 

 endangerment of the public health. 



