PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 381 



Mr. Fisher. — Have the gases ever been heated for the osyhydrogen 

 blowpipe ? 



Prof. Seely. — Not that 1 am aware of. I do not think much of the hot 

 blast, however; the expansion of the air tends to diminish the intensity of 

 the heat, counteracting to a considerable extent the effect of heating the air. 



The Chairman.* — I see in the room our old friend, Mr. Everett. He is now 

 located at Cleveland, Ohio, as a manufacturing chemist, and has made a 

 great many experiments on coal oil. He can probably give us some inter- 

 esting information on the subject. 



Mr. Everett. — Coal oil is not now manufactured. Petroleum is so cheap 

 that the manufacture of coal oil does not pay. We call the petroleum 

 "coal oil" from habit, but it is a misnomer. I have nothing of interest to 

 say in regard to either substance. 



Mr. H. J. Callo. — I came over from Jersey City, and have sat all the 

 evening hoping to hear something about fuel, but I have been disappointed. 

 I am a chemist, but at present am engaged in distilling at Jersey City. I 

 have adopted some improvements in burning fuel, by which I save twenty- 

 five per cent, of the cost. This saving is effected by burning a cheaper 

 material. I burn the fine coal dust. The only difficulty is in getting a 

 man to feed the fire properly. The dust must be thrown in very frequently, 

 and spread evenly over the grate. I formerly paid $12,000 a year for coal, 

 but now it costs me $9,000. Yet I have to turn round and pay a man 

 three or four dollars a week more, in order to get one who can fire with 

 this fine dust. 



Mr. Overton. — I will remark in this connection, Mr. Chairman, that my 

 fan is just the thing for blowing a fire with fine coal. Unlike other rotary 

 fans, it has a piston which will work against pressure, I believe that all 

 you can do in generating heat from carbon is to burn it completely — com- 

 bine with each atom of carbon two atoms of oxygen. And I will further 

 remark that I believe the time will come when a far more intense heat will 

 be used for generating steam, with a small extent of boiler surface. You 

 have probably seen the accounts of the locomotive that was altered iu 

 Jersey City. The pipes were reduced in length one-half, and the boiler 

 made more steam. 



Mr. Dibben. — Was not the length of the fire box increased to the samp 

 extent as that of the pipes was diminished ? 



Mr. Overton. — I do not know how that was. 



Mr. Dibben. — It was. 



Mr, Fisher. — Several years ago a Mr. Bennett had an engine here in 

 which the air was compressed, and I should like to know if there is any 

 one present who is acquainted with the results of that experiment. The 

 fire box was inclosed and the air was forced into it by an air-pump; a 

 safety vavle opened when the pressure reached a fixed limit, and allowed 

 the products of combustion to escape into the boiler. Tiie engine was 

 placed in a steamboat, and very good speed was obtained from a moderate 

 sized engine. But the valves were cut out by the ashes, and the plan was 

 abandoned. 



Mr. Churchill. — I have found that the best plan for burning gas as fuel, 

 is to surround the jet with a series of concentric chirameys, A slight 



