126 
that obtained by heating bones to a red heat in closed vessels. 
It appears to have a powerful effect in absorbing and oxidising 
noxious gases probably greater than any other species of 
charcoal. I have read an interesting lecture given by Dr. 
Stenhouse of London, many years ago, which was kindly 
placed in my hands by our worthy President Mr. Binney. 
He made some experiments to decide the value of different 
charcoals, and came to the conclusion that animal, more 
properly speaking bone charcoal, was best adapted for ab- 
sorbing colour from liquids, but wood charcoal was best 
adapted for absorbing noxious gases ; he however draws a 
distinct line between the capabilities of a charcoal to simply 
absorb on the one hand, and to absorb and then oxidise or 
decompose noxious gases on the other, but he does not men- 
tion the results of any experiments made with the charcoal 
under consideration. The following analysis of this sub- 
stance was made and given to me by Mr. Spiegel of Oldham. 
Per Cent. 
Water 30’51 
Organic and volatile matters 4‘52 ■) ^ 
Carbon 22’79 i 
Sand and insoluble matter 16'30 
Oxide of iron and alumina 12*66 
Lime 2‘11 
Magnesia *50 
Sulphuric acid 5*33 
Potash 3*117 
Soda *759 
Ferrocyanic acid. *315f 
Traces of phosphoric acid, carbonic acid, and loss... 1*059 
100*000 
In conclusion I have to thank Mr. Ralph Clifton, of 
Stockport, for the care and manipulative skill which he has 
shewn in making the analysis of the sample of drainage 
water. 
* Containing nitrogen=aramonia 
t Existing as Prussian blue 
1*035 
