> ■ • >j £)■■. Beddoes on fotne appearances attending 
iron is iron imperfectly reduced, or, in other words, that it 
contains a portion of the bafis of vital air, the oxygene of M. 
Lavoisier. 2. That it contains a portion of plumbago, with 
which grey caft iron moft abounds. 3. That plumbago con- 
fifts of iron united to charcoal. 4. That fixed air, which I 
would rather call carbonic acid air, confifts of oxygene and the 
conftituent parts of charcoal. 
The heaving or fwelling motion, fo confpicuous in the pro- 
cefs, is doubtlefs owing to the difcharge of an elaftic fluid ; 
and the lambent deep blue flame, breaking out in fpots over the 
whole furface, (hews, that this elaftic fluid is an inflammable 
gas of the heavy kind. That no doubt might be left upon the 
former of thefe circumftances, I directed the workman to take 
out, at two different periods, a quantity of the metal where it 
was working moft ftrongly. Both proved, on examination, to 
be fpungy, cellular, and full of bladder holes. 
The heavy inflammable air, I imagine, is produced in this 
manner. The oxygene of the imperfeCtly reduced metal 
combines with the charcoal to form fixed air ; at the fame time 
another portion of charcoal is thrown into an elaftic ftate, that 
is, into inflammable air, and burns on the furface with a very 
deep blue flame, on account of the admixture of fixed air. 
The heat which is fo obvioufly generated in the mafs at the 
beginning of the fermentation, I attribute to the combination 
of the oxygene and charcoal ; a fad which, with feveral 
others as I have already remarked on another occafion *, Ihews, 
if not the falfehood, at leaft the imperfection of the modern 
doCtrine on the fubjeCt of heat. The acidifying principle, it 
would appear, has fome power of generating heat independant 
of its condenfation. Here abundance of elaftic matter is 
■ ' ' _ v , . .... y / . . - . ' 
* Chemical opinions of a philofopher of the laft century. 
dif- 
