52 ANNUAL OF SCIENTIFIC DISCOVERY. 



by water, or by the impurities present in the atmosphere of large 

 cities. Their process may prove to be a rival to that of Mr. Spil- 

 ler, before mentioned, which, according to present appearances, 

 is likely to be the most successful of all the schemes now on trial 

 for this purpose. 







USE OF PETROLEUM AS FUEL. 



A remarkable trial took place in Boston harbor in June, 18G7, 

 to test the use of crude petroleum instead of coal for steam .ves- 

 sels. The United States gunboat Palos, equipped with petroleum 

 apparatus, left the Charlestown Navy Yard, made a trip of 25 

 nautical miles in 1 hour and 55 minutes, and used less than 4 

 barrels of petrohuim to accomplish the work for which 6 or 8 tons 

 of coal would have been required. 



In this experiment, petroleum was supplied from two large iron 

 tanks placed on deck, each tank having a glass gauge at its side, 

 to indicate the height of the petroleum, and a vent-pipe on the top 

 to permit the escape of vapor. From these tanks the petroleum 

 was conducted by half-inch pipes into iron retorts heated by 

 burners placed beneath them, being instantly vaporized. This 

 vapor, in burning, was mixed with steam decomposed by pass- 

 ing through pipes partially filled with iron filings, and with air 

 forced in by a common air-pump. The heat thus generated was 

 intense, and the combustion so perfect that no smoke was per- 

 ceptible. The oil is only supplied as fast as it can be converted 

 into vapor. The supply of steam and air and oil is graduated by 

 means of small throttle-valves, and the fire increased or dimin- 

 ished at will. 



A great merit of this invention is its simplicity, cheapness, and 

 durability, there being no complicated machinery and no sul- 

 phur in the liquid fuel to aifect the iron. Thus far, in the course 

 of the experiments, the result obtained is highly satisfactory to all 

 concerned. It is said that 3 men with the use of petroleum 

 can do the work of 20 men in running the machinery. As a 

 matter of room-saving the use of petroleum on board of vessels 

 is very great. The Palos has capacity to stow away coal sufficient 

 to last 6 days ; petroleum enough can be stowed in the same ves- 

 sel to last for 20 days, and that, too. in places inconvenient or 

 unavailable for freight. The inventor is Col. Henry R. Foote. 



A subsequent trial was even more satisfactory than the previous 

 experiment. The rate of 12 knots was made against wifld and 

 tide, with a pressure of 32 pounds of steam. The vessel was 

 14 inches deeper in the water, and was in bad trim ; steam was 

 raised in 25 minutes, when it would have required 3 to 4 hours to 

 have obtained a pressure of 35 pounds with afire of anthracite coal. 



Calculations of the relative economy of coal aiid oil, as fuel for 

 ocean steamers, should take into account the item of firemen and 

 coal passers, their wages and quarters, in addition to the differ- 

 ence in weight and space of furnaces and of boilers. In the ex- 

 periments on board the Palos, it was found that with 3 of her 

 4 boilers, and the attendance of 3 men, 50 per cent, more rev- 



