56 ANNUAL OF SCIENTIFIC DISCOVERT. 



gas in our. houses, and, so far as our knowledge goes, petroleum 

 can be more readily supplied than coal in the majority of the sea- 

 ports we frequent. The first demand will be for war ships, then 

 for express steamships, then for river boats, then for locomotive 

 engines, then for the steam rollers that have yet to level our 

 macadamized streets, then for traction engines, then for the road 

 engines which will travel on sunk rails in single lines at 10 miles 

 per hour on the highways and turnpikes, for the movable and 

 portable -will always demand a better fuel than the stationary, 

 and will pay a better price. Gradually the factories will follow, 

 and lastly the dwellings. 



** But we have not yet got the petroleum in sufficient quantities. 

 Quite true, and, as with gas-lig iting, we have to begin. But the 

 petroleum appears to be a drug in the United States, and it will 

 come thence till such time as we can procure it more cheaply at 

 home. As regards risk, there need be no more than with any ordi- 

 nary fire. It is not like gunpowder, which explodes in masses ; but 

 simply an oil, which is only combustible in such quantities as may 

 be sufficient to feed the fire ; it involves less risk than ordinary 

 house gas." 



A recent report to the Navy Department expresses the belief 

 that petroleum cannot compete with coal for use in vessels of war. 

 Jt does not at present appear that it can be used with entire 

 safety where two other dangerous explosives are necessary, 

 namely, gunpowder and steam. 



OVERHEATED STEAM BOILERS. 



Notwithstanding the clearness of theoretical deduction, and the 

 results of carefully conducted experiments, the opinion is still 

 prevalent that a violent explosion must be immediately produced 

 by turning on the feed water into an empty boiler with the plates 

 even red-hot. To clear away any misapprehensions and doubts 

 which may still exist, attention is called to the following experi- 

 ments made in Manchester, England, by the chief engineer of the 

 Manchester Boiler Association, the results clearly showing that the 

 danger of injecting water into red-hot boilers has been greatly ex- 

 aggerated, and that the explosion of boilers cannot be attributed 

 to this cause. The boilers were three in number, and of the ordi- 

 nary household circulating class. 



The first was made of copper, weighed 62 pounds, and meas- 

 ured 14^ inches in height, 11| inches in width, by 13| inches in 

 depth at the bottom, and about 8 inches at the top, having an in- 

 ternal capacity of about I cubic foot. This was surrounded by a 

 brisk fire, empty, and allowed to renrdn till the bottom became 

 red-hot, and lumps of lead loosely laid on the top, the coldest 

 part, freely melted. Then water was suddenly let in through a 

 half-inch pipe. No explosion took place; the boiler was not 

 stirred from its seat, nor did it evince the slightest sign of internal 

 commotion ; all that took place was a rush of steam through an out- 

 let seven-eighths of an inch in diameter left on the top of the boiler. 

 It was necessary to have this opening, or the water would not have 



