ON THE GASES EVOLVED FROM IRON FURNACES. 145 
whether’ carburetted hydrogen ought to be considered as an essential con- 
stituent of the gases, and whether its absence in the cases cited is due to an 
error in Ebelmen’s analyses. 
It is well known that ordinary charcoal is very far from being pure carbon, 
and that it in fact contains about 20 per cent. of foreign matters, which 
escape as gaseous and liquid products when it is heated to redness. If car- 
buretted hydrogen form, as is generally supposed, an essential constituent of 
the gases resulting from the distillation of wood-charcoal, it is quite clear that 
it cannot be absent from the gases of furnaces supplied with that fuel. Al- 
though the presence of carburetted hydrogen in the gases obtained by the 
distillation of charcoal is generally acknowledged, we have thought it not 
superfluous to put this fact beyond all doubt by a renewed examination. The 
charcoal subjected to experiment was heated in a narrow glass tube, con- 
nected with a long dry tube to retain the liquid products of distillation, and 
the gases, after passing through this, were collected over mercury. In order 
to remove any elayl or hydrated oxide of methyl, which might possibly have 
accompanied the gases, they were conducted through a long tube filled with 
fuming sulphuric acid, attached to which was another tube moistened with 
water. The analysis of the gases was then effected in an exact eudiometer, 
and according to the methods which we describe in an after part of this report. 
I. A specimen of very well-burnt charcoal, from beech-wood, yielded a 
gas of the following composition, according to volume :— 
Carbonic acid » « 23°65 
Carburetted hydrogen. . - 11°00 
Carbonic oxide . . .. - 15°96 
Hydrogen. . . - - - - 49°39 
100°00 
II. A good specimen of charcoal from fir-wood, also well-burnt, gave a 
gas constituted as under. 
III. 0:6500 gramme of oak-charcoal, of a similar nature to the last, left 
behind 0:47 carbon, and yielded 70 cubic centimetres of gas at 0° C. and 0°76 
bar., consisting as under. 
IV. 0°733 imperfectly burnt beech-wood charcoal, pulverulent, and of a 
blackish-brown colour, left 0°443 carbon and 250 cubic centimetres of gas 
at 0° C. and 0°76 bar., which gas was composed as under. 
II. Ill. IV. 
Gas of Gas of Gas of 
Fir-charcoal. Oak-charcoal. Beech-charcoal. 
Carbonic acid. ......- 15°96 19°58 35°36 
Carburetted hydrogen .. 20°32 20°75 20°78 
Carbonic oxide ...... 13°62 90°57 14°41 
. Hydrogen... .... +. 50°10 39°10 29°45 
; 100:00 100:00 100-00 
If we assume the most unfavourable condition to the calculation, that the 
charcoal used in the furnace of Clerval was of the most select quality, which 
could not have been the case, it follows from the analysis and consumption 
of charcoal at that place, that no less than 479 cubic feet of light carburetted 
hydrogen must have escaped from the top of the furnace every hour, and yet 
not.a trace of this large quantity is to be found in Ebelmen’s analyses. The 
above experiments prove beyond contradiction that the carburetted hydrogen 
found by Scheerer and by us in the gases from charcoal, is actually an essen- 
" 1845. L 
q 
\ 
. 
. 
} 
