44 
Iron „ 
and weighed 249 grains ; a produce in iron from the raw 
stone = 28.5 per vent. : the vitrid mass was found to 
w igh 354 grains ; the loss of volatile mixtures was there « 
fore 272 grains, or 31 per cent. The fracture of the re- 
gums now obtained was still white, though not allied to 
any degree of crystallisation, and its surface smoother 
and less oxydated. The glass produced in this experi- 
ment was of a deep brown shining colour, in many 
places porous, and enriched with fine tints of colouring. 
3d, The same experiment was repeated upon 875 
grains of a fine calcareous * iron-stone. The fusion of this 
required a violent heat of seventeen minutes, during which 
time the disengagement of a gaseous substance w 7 as most 
evident ; in other respects it exhibited the same features* 
when in fusion, as the two former : the degree and length 
of heat conveyed was nearly the same ; and the result j 
obtained was a button of carby- oxygenated crude iron 
weighing 261 grains; a produce in iron equal to 30 per 
cent, from the raw iron-stone ; fused earths, now reduced 
* I omitted to mention (p. 37) another method of ascertaining the 
quantify of calcareous or limestone earth in an ore. Pure limestone 
contains 44 parts in 100 by weight of air (carbonic acid gas). Taker 
a Florence flask, or the round bottom of a Florence bask, put it on 
one side of a pair of scales ; pour into it one dram by measure or , 
100 grains by weight of spirit of salt, and as much water. Put 
weight in the other scale to balance this. Then pour into the acid 
liquor your ore in powder, and let it remain for an hour. What- 
ever limestone it contains will be dissolved, and the quantity can 
be told from the weight lost : suppose the loss 10 grs. : then as 44 
is to 100, so is 10 to the limestone contained in the ore. This will 
be accurate wherever the iron in the ore is not in a metallic stati/ ; 
if it be, air will be given by the iron, which a chemist can. 
separate by means of lime water. But few ores will be liable to j 
this uncertainty. 
Qxyd , Oxydation , metal combined with xoygen or pure air, 
which must be separated from it by means of carbon or charcoal 
Carbonated , carbonation , the uniting pure charcoal to an ore* 
which converts it into a metal. T. CF 
