Miscellanies. 183 



bellows, being hooked up to the cross beam, there was of course as 

 large a cavity as possible, filled, at first, with common air. The wet 

 wood, buried in hot ashes and cinders, necessarily emitted, during the 

 whole time of its carbonization, a great deal of carburetted hydrogen 

 gas, mixed with carbonic acid, and probably also with carbonic oxide. 

 The pressure of the covering of ashes and cinders obstructed the 

 escape of these gases into the air of the room, and forced a part of 

 them into the bellows, and when the explosive proportion was attain- 

 ed, the mixed gases were kindled by the fire in the forge, just as a 

 musket or cannon is discharged by fire applied at the touch hole. 

 , The most powerful explosive proportions are one seventh or one 

 eighth of the inflammable gas to six sevenths or seven eighths of com- 

 mon air, and this proportion might be, under the circumstances, read- 

 ily attained. To chemical readers, it is not necessary to expatiate 

 upon circumstances which are so familiar to them ; such explosions 

 are not uncommon ;. but. commonly they are not destructive. Even 

 philosophical laboratories are usually furnished with forge bellows. 

 In the laboratory of Yale College, we have, in a number of instances, 

 witnessed explosions arising, evidently, from the suction of inflamma- 

 ble gas into the bellows, especially during the cessation of the blow- 

 ing and the gradual descent of the lfiwer plank of the bellows, which, 

 in consequence of the weight usually attached to it, falls slowly 

 as the lever ceases to work, and thus draws the inflammable gas with 

 it, into the bellows* We have never seen the bellows actually torn 

 by the explosion, but we have seen heavy weights thrown, suddenly, 

 from the top, by the violent jerk, and have heard repeatedly a loud 



detonation. 



In the case related by Mr. Jones, it is obvious that the accident 

 will be effectually prevented, by hooking up the lower part of the 

 bellows instead of the upper, and pressing down the upper by weights 

 so as to exclude, as completely as possible, the common air, and also 

 to prevent the entrance of inflammable gas. When the working of 

 the bellows commences, in the morning, it would be well to begin with 

 short and quick movements of the lever, in order to establish a cur- 

 rent of common air through the bellows, before there is an opportu- 

 nity for inhaling inflammable gas. It is scarcely necessary to remark, 

 that the tube or tuyere of the bellows at Newburyport escaped with- 

 out injury, because it was very strong, and because the quantity of 

 explosive gases contained in it was, necessarily, very small ; just the 

 opposite facts were true of the body of the bellows, constructed as 

 it is of leather and wood. 



