[3] WORK OF STEAMER ALBATROSS. 373 



To determine the result of the fracture of an incandescent lamp in a 

 coal bunker where there is coal gas : 



(1) A 2-quart butter-jar, a (Plate I) was fitted with an air-tight wooden 

 cover, ft, through which the gas-tube, d, electric cable, i, and gas-burner, 

 h, were passed, all having air-tight joints. The firing bolt,/, also passed 

 through the cover, but moved freely, the joint being made air-tight by 

 a ring of putty pressed gently around the rod. A 10-caudle B lamp, c, 

 was placed in the jar and the cover screwed on. Gas was introduced 

 from a city lamp through the hose, c, and tube, (?, and was lighted at h, 

 giving a full flame. The electric lamp was lighted and allowed to 

 burn several minutes, then fractured by releasing the weight, #, which, 

 striking the collar on /, drove the bolt down and shattered the lamp. 

 The gas did not ignite, but the flame was extinguished. 



(2) The experiment was repeated, except that the base of the lamp 

 and bottom of the jar were covered with gunpowder. The lamp was 

 shattered a second time, without igniting gas or gunpowder. The flame 

 was extinguished. 



(3) The experiment was repeated, except that immediately preced- 

 ing the fracture of the lamp the gas was turned off at /i, leaving the jar 

 air-tight and charged with a full pressure of gas. Neither powder nor 

 gas ignited. 



(4) Placed a lighted candle in the jar and turned on the gas, which 

 ignited immediately. 



(5) Placed a lighted bunker lamp (lard oil) in an upturned barrel, 

 upper head out, led the hose to bottom of barrel and turned on the gas, 

 which escaped about five minutes, but gas did not ignite. 



(G) Placed the barrel on its bilge and introduced the bunker lamp and 

 gas as before. Gas ignited in forty seconds. 



There being a vacuum in the incandescent lamp its fracture would 

 cause a strong indraught to fill the void. The burner, /t, being closed, 

 excluding air, the gas would rush in until the full pressure was at- 

 tained. 



During the first two experiments with gas the burner was left open 

 aud lighted : 



(1) To show that the jar contained a full supply of gas. 



(2) To admit a quantity of air when the fracture of the lamp occurred, 

 in order to increase the inflammability of the gas. The fact of the burner 

 having been extinguished at each trial demonstrates the introduction 

 of air by the indraught before mentioned. 



Conclusions : 



(1) The fracture of an incandescent electric lamp will explode gun- 

 powder when it is brought in contact with the carbon of the lamp. The 

 latter is consumed so rapidly after its contact with the air that there 

 are no burning fragments scattered about. 



(2) The fracture of an incandescent electric lamp will not ignite illu- 

 minating gas. 



