440 NOTICES OF THE MEETINGS [May 5, 
lized and amorphous, were here exhibited, and Tables exhibiting 
numerous analyses of them were referred to. | 
Theory of the Blast-Furnace-—Though much has been written on 
this subject, it can scarcely be said that any very sound scientific 
views were entertained respecting the theory of the Blast-Furnace 
previous to the beautiful researches of Professors Bunsen and Playfair, 
and more recently those of the late lamented Professor Ebelmen, on 
the gases evolved from the furnace at different depths. 
Tables in which these experiments were compared were referred 
to ; the difference in the results may in a great measure be explained 
by the circumstance that the English furnace (Alfreton, in Derby- 
shire) was working entirely with coal, whereas the Seraing furnace, 
on which M. Ebelmen’s experiments were made, was working with 
coke alone; this would at any rate explain the difference as relates 
to the carburetted hydrogen, and hydrogen gases; mere traces of 
the former were found by Ebelmen, while Bunsen and Playfair 
found as a maximum 8°23 per cent. of the former, and 12°42 per 
cent of the latter. As it is probable, however, that neither of these 
gases takes any share in the reduction of the ore, their presence or 
absence will not materially interfere with the discussion of the 
theory of the blast-furnace. 
Both series of analyses shew, what at first sight appears most 
remarkable, viz.: that the gases in the immediate neighbourhood of 
the blast do not contain a trace of carbonic acid; shewing that 
powerful oxidizing and de-oxidizing actions must take place at that 
point. Here also in the English furnace were found Cyanogen and 
vapours of Cyanide of potassium; in the Seraing furnace no Cyanogen 
was detected, but abundance of Cyanide of potassium and vapours of 
oxide of zinc. The Cyanide of potassium, which, doubtless from its 
powerful reducing action exercises an important influence on the 
reduction of the stubborn forge cinder, is formed by the action of 
the nitrogen of the blast, on the red hot carbon of the fuel in the 
presence of potash derived from the ore. Bunsen and Playfair cal- 
culated that in the Alfreton furnace 224°7 lbs. of this salt were pro- 
duced daily. 
The conclusions deduced by Bunsen and Playfair from their gas 
analyses are, that the reduction of the iron minerals, and the disen- 
gagement of carbonic acid from the limestone, takes place at a depth 
of between 24 and 25 feet, that is in the boshes of the furnace, the 
cone or body of the furnace being entirely taken up in the process 
of coking the coal. Ebelmen thinks, on the other hand, that the rapid 
diminution of carbonic acid and corresponding increase of carbonic 
oxide in descending the furnace, which are shewn by his analyses, 
indicate conclusively that an energetic reduction of ore takes place in 
the vicinity of the mouth of the furnace, that reduction being 
effected by carbonic oxide under the influence of the high temperature 
of the ascending gases without any change in the volume of the gas, 
and without any consumption of fuel. This mutual relation of the car- 
