324 Chronicles of Science. [April, 



a shot penetrated the vessel containing the petroleum, and allowed it 

 to escape in proximity to the boiler fires ? 



In answer to these objections of Dr. Paul, Mr. Eichardson, the 

 patentee, asserts that the relative heating-powers of petroleum and 

 coal, as depending upon their chemical composition, is not the ques- 

 tion ; the ability of each to create steam is the real matter to be con- 

 sidered. Petroleum, as steam fuel, can be very nearly fully utilized : 

 it produces no ash, submits to mechanical management, and makes 

 little or no smoke ; does not require any strong draught or current of 

 air like coal, which will not burn without it, the consequence being 

 that a very considerable portion of the fuel is lost, as waste heat, in 

 the chimney. In careful experiments by Mr. Wye Williams, to ascer- 

 tain the best form of boiler to obtain the greatest amount of heat from 

 coal, he gives the temperature of the waste heat in the first experiment 

 as 1060° ; in the second, 760° ; and in the third, 635°. If these are 

 the temperatures, with a consumption of only three-and-a-half cwt. of 

 coal in each experiment, what would be the temperature of the waste 

 heat in the chimney of a furnace burning from twenty to thirty tons of 

 coals per day '? We know the current is so strong that it often carries 

 up small coal and cinders along with it ; that the heated gases often 

 take fire by a spark from the furnace, and burn at the top of the funnel 

 with a fierceness almost equalling the flame from a blast furnace. Is 

 this flame or waste heat employed in creating steam ? And how much 

 of the coal is utilized ? In practice, Mr. Eichardson says, the ratio 

 of the heating-power of petroleum and coal is about 1 - 4 to 4. The 

 patented grate, which burns petroleum through a porous matter, proves 

 that one ton of petroleum does as much work as five tons of coal. If 

 four tons out of five are saved for freight space, the price of the latter 

 being 11. per ton, the profit on every ton of petroleum would be 

 14Z. 15s. — the coal at 15s., the petroleum at 111. per ton. But a ship- 

 owner might not select the American crude oil at 111.; he could take 

 the Flintshire coal oil, which is quite as good for his purpose, and 

 costs only about 10Z. per ton. The average price of coal on a long 

 voyage would be low at 21. per ton. Taking the prices and the freight 

 at the reduced sum of 61. per ton in a ship requiring 500 tons of coal, 

 and using instead 100 tons of petroleum, the profit by the exchange 

 would be 2,000Z. Eespecting the highly dangerous inflammable 

 nature of petroleum, Mr. Eichardson considers it to be greatly exag- 

 gerated. If the oil were contained in cast-iron cases, securely closed, 

 no vapour could escape ; or if the small amount of spirit which pro- 

 duces the inflammable vapour was first extracted, the residue, the 

 burning oil and heavy petroleum, would be no more dangerous than so 

 much lard or spermaceti. 



Lenoir's gas engine, which has been at work in Paris for some 

 time past, may now be seen daily in use in London. In appearance, 

 the Lenoir engine is very much like a horizontal steam-engine, having 

 a cylinder, piston, crank, shaft, and fly-wheel. The cylinder has the 

 necessary slide arrangements for the admission of coal gas, and 

 atmospheric air in due proportions, which, at the proper moment, are 



