producing Ignition in Charcoal in Atmospheric Temperatures, 3 



Before I proceed to an account of my own direct experi- 

 ments, I will describe here another instance of spontaneous 

 combustion which occurred casually. About 2000 lbs. weight 

 of charcoal were loaded at Cornbrook, in the cart of Messrs. 

 Williamson and Co., powder-manufacturers of Fernelee, 

 near Buxton. The charcoal had been made several days be- 

 fore, and had lain freely exposed to the open air. No indica- 

 tions of combustion could be perceived. After being taken 

 out of the cart at Fernelee, it was left for the night, and the 

 next day finely pulverized as a preparation for making gun- 

 powder. It was then thrown into a heap; and no appearance 

 of a tendency to ignite ensued. This was on the Saturday 

 evening; and on Sunday, the building which contained it 

 was observed to be on fire. The fire must have commenced 

 with the charcoal, as every other source of heat was carefully 

 excluded, on account of the gunpowder manufactory. 



These, and a number of other accidents which have arisen 

 from the same cause, united with the opportunities which I 

 have possessed as a manufacturer of charcoal, have led me to 

 take particular interest in the subject. 



Colonel Aubert's paper, which I have already alluded to, 

 and an abridged translation of which appeared in Dr. Brew- 

 ster's Journal for April last (1831)*, placed the subject in so 

 striking a point of view, that I came to the determination of 

 making, for my own satisfaction, a few experiments, which I 

 shall proceed to describe. 



Exp, 1. — 120 pounds of charcoal, slightly pulverized, were 

 put into a flour-barrel, and a leaden tube, of an inch and a half 

 in diameter and 14 inches long, inserted in the middle, to hold 

 a thermometer. The temperature of the charcoal when put 

 into the barrel was 60°. In two days the charcoal acquired 

 a temperature of 74° ; from that time the temperature gradu- 

 ally diminished until, in two days more, it was reduced again 

 to 60°, — the temperature of the surrounding atmosphere. 

 This charcoal was rather old, having been made several weeks, 

 and afterwards freely exposed to the open air. 



Exp. 2. — 120 pounds of fresh charcoal, pulverized as before, 

 were put into the vessel used in the preceding experiment. 

 The charcoal was then at 70°, and the surrounding air at 62°. 

 In 24 hours it had acquired a temperature of 90° ; in 36 hours, 

 of 110°; and in 48 hours, of 120° : from this time the tempe- 

 rature fell ; and in 48 hours more it was down to 70°, as at the 

 commencement. 



* An abstract of Col. Aubert's paper was also given in Phil. Mag. and 

 Annals. N.S. vol. ix. p. 148.— Edit. 



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