259 
converting cast into malleable Iron . 
most rapidly extricated on the first impression of a red or 
white heat. Afterwards they came over much more slowly ; 
during a considerable part of this experiment 3*011 might count 
twelve slowly between every air-bubble. 
When the utmost power of the furnace had been exerted for 
three hours, a phenomenon occurred which produced some 
surprise in every person present ; and there were several who 
had been abundantly accustomed both to chymical and metal- 
lurgical operations. A considerable absorption took place, and 
for about half an hour, it was necessary to blow air up the glass 
tube, to prevent the water from rising into contact with the iron. 
It afterwards appeared that the lead of the glazing was revived, 
which sufficiently explains the absorption. 
586 grains only of the iron had been completely fused. 
The surface of two of the unmelted lumps was curiously co- 
vered with numerous small blisters of metallic lead. 
About seven hours after the fire was first kindled, it was 
discovered that the apparatus had failed. I had examined the 
air that came over immediately before this accident, both by 
means of lime-water, and milk of lime, without discovering 
any vestige of carbonic air. 
The iron weighed altogether three grains more than at first. 
But the adhering lead, and a quantity of lead also which was 
incorporated with the iron, concealed a real, and probably a 
considerable, loss of weight. The phaenomena it exhibited, 
when put into weak vitriolic acid, and the vitriolated lead 
which was formed, indicated the presence of this metal in all 
the superficial parts of -the mass. When it had been kept some 
time in vinegar, it dissolved readily enough in vitriolic acid at 
first, but the solution soon ceased, or became very slow. 
