MECHANICS AND USEFUL ARTS. 53 



olutions of the wheels were obtained than heretofore with coal 

 under all 4 boilers, with the attendance of 20 men. But the 

 greatest difference may be realized from a more perfect utilization 

 of the force contained in the fuel. It is well known that as yet 

 but a small per centage of the theoretical power of fuel has been 

 obtained through steam. Coal heat is mostly applied by radia- 

 tion ; oil, with proper apparatus, may be brought, in a state of 

 combustion, mainly into direct contact with the boiler surface. 



The interest and figures involved are enormous ; they affect the 

 water transportation of the whole world, .whether by river, lake, 

 or ocean, reducing expense and time, and about doubling the 

 freight capacity of sea steamers. It is equally applicable to loco- 

 motives, and especially available on the Pacific railroads. 



Mr. A. C. Stimers, who witnessed the experiments on board the 

 Palos, in a letter to the "New York Times," says, in regard to the 

 source of the steam that is passed into the retort that generates 

 the heat for raising steam in the boiler: "The introduction of 

 superheated steam into the retort where the oil is vaporized is not 

 essential to the making a fire and getting up steam, butt it is to 

 burning said vapor with the completeness of combustion neces- 

 sary for it to compete with coal as a steam fuel. In burning the 

 vapors of petroleum it is necessary that every particle of the 

 vapors shall come into close contact with a corresponding particle 

 of atmospheric air; but air and the vapors of the oils appear to 

 have the same repellent qualities as oil and water, and do not mix 

 enough to prevent the formation of a thick black smoke, and the 

 heat developed is comparatively very small. 



* All who have attempted the use of petroleum for a steam fuel, 

 appear to have early learned the great advantage of introducing 

 superheated steam to the vapors. When this is done, the air 

 mixes readily with the compound, and a more complete combus- 

 tion is effected. 



" Although, as I have already stated, steam could be raised in a 

 boiler from burning the oil vapor only, yet it is done much more 

 quickly and pleasantly if a supply of steam can be had. 



"The first experiments tried to test the practicability of em- 

 ploying petroleum for generating steam were by Shaw & Linton, 

 in Philadelphia. I was member of a Board of Naval Engineers, 

 ordered by the Department to conduct and report upon the ex- 

 periments. They continued during 5 months, and our report is 

 dated May 5, 1863. 



"In that arrangement, ' the apparatus used was an ordinary 

 tubular locomotive form of boiler containing 15 tubes, 2 inches in 

 diameter and 56 inches in length ; a small steam engine, in con- 

 nection with it, operating a pump supplying water to the boiler; 

 with an additional boiler, of very small dimensions, placed in a 

 heating apparatus, to provide a steam jet, previous to firing up 

 with the oil, in the absence of other means for procuring the 

 necessary artificial draft until steam was raised in the larger 

 boiler. 



" "this would be a good arrangement for Colonel Foote to employ 

 with his process. The great merit of Colonel Foote's process over 



