618 Foreign and Miscellaneous Intelligence. 



edge, for thermometers ; the time, from the end of the carboni- 

 zation to the arranging the casks, was sixty hours. In about six- 

 teen hours the maximum of temperature occurred ; it was, for the 

 distilled charcoal, 41 C. (74 F.) above that of the place, which 

 was at 12 C. (53.6 R), and for the other 28 C. (50.4 F.). In- 

 flammation did not take place apparently, because the casks were 

 well covered, and thus access of air prevented. 



On repeating the experiment, in every point, except that free ac- 

 cess of air was allowed, inflammation of the distilled charcoal took 

 place. When put into the cask it was at 11, in two hours it 

 had become 40, in twenty-three hours 70, twenty-nine hours 75, 

 and in thirty-three hours from the pulverization it inflamed. When 

 about to inflame, smoke was seen to rise from the centre, especially 

 from the thermometer-hole ; this gradually increased, and the inflam- 

 mation was first observed about five centimetres (1.97 inches) below 

 the surface of the charcoal ; it rapidly extended to within twice that 

 distance from the staves. On tilting the cask, a layer of charcoal, 

 15 or 20 centimetres (4.9 or 7.87 inches) thick, fell out, from which 

 proceeded long jets of fire ; the rest did not appear to be inflamed, 

 the hand could easily be held in it ; but that gradually also heated, 

 and next morning was on fire, though the night had been very cold. 

 The other charcoal heated, but did not inflame. During the tritu- 

 ration of the charcoal, the air in the casks was not altered. It did 

 not precipitate lime-water, and contained no carbonic acid. 



Twenty-five parts of each of these charcoals were put, imme- 

 diately after pulverization, into capsules, and into jars full of air, 

 confined by water. In three days the charcoal absorbed much air, 

 and increased by 1 J part ; the other charcoal had also absorbed 

 much air, and increased by 1 . 3 part. 



Many other experiments were then tried : charcoal allowed to re- 

 main exposed to air twenty-four hours before trituration did not 

 inflame. The mass also had great influence; upon doubling the 

 quantity of the charcoal made in open vessels, that also inflamed 

 twenty-two hours after pulverization. In this case the heat was highest 

 near the surface rather than lower down, and the augmentation 

 in weight of 84 kil. was only 280 grammes, or l-300dth part ; the 

 inflammation took place only in a small quantity of the charcoal near 

 the middle of the upper layer. A capsule of lime-water placed on 

 the carbon did not indicate formation of carbonic acid before the 

 charcoal inflamed. 



In another experiment, two equal portions of 42 kil. each were 

 placed, one in an open and the other in an inclosed vessel ; the first 

 inflamed, the second did not ; so that the absorption of air appears to 

 be the cause of inflammation. 



On allowing five or six days to pass between the carbonization 

 and pulverization, no combustion of the powder occurred. When 

 circumstances, as to age, &c., were the most favourable possible, 

 portions of 45 and 30 kil. inflamed, a portion of 15 kil. did not. 



