77 



" It was upon a knowledge of these facts that I founded the 

 inventions for which I obtained patents. My first efforts were 

 directed to the diffusion of the vapour of coal naphtha through 

 hydrogen gas ; and to effect this object with economy and 

 brilliancy of the resulting light, I contrived a variety of 

 instruments. 



" In the specification of my patents I minutely described 

 some of these; a brief account of one will here suffice, as the 

 details now constitute one of the public records. Into this 

 instrument, which is in the form of a lamp, a stream of hydro- 

 gen is passed, and dispersed by a tube having many small 

 holes into a small cylinder, also pierced with holes, and round 

 which a piece of iron wire-gauze is rolled. This wire-gauze 

 roll is continually kept wetted, either with one of the less vo- 

 latile kinds of coal naphtha, or with naphtha obtained from 

 resin or from Indian rubber, or with spirit of turpentine, or 

 fine spirit of tar, or other volatile hydro-carbon. The hydro- 

 gen passes out through the holes of the burner of the lamp, 

 and, being kindled, generates much heat, which, being quickly 

 transmitted downwards to the wire-gauze, heats the volatile 

 hydro-carbon with which it is constantly impregnated, and 

 converts it into vapour. The vapour mixes with the hydro- 

 gen, and the mixture is now much of the same nature as coal 

 gas, or oil gas, or resin gas ; it burns with great brilliancy, 

 provided that the parts of the lamp bear a proper proportion 

 to each other. 



" The office of the roll of iron gauze is to raise the hydro- 

 carbon by capillary attraction through its meshes and convo- 

 lutions, and thus to present the hydro-carbon on extensive sur- 

 faces to the solvent power of the hydrogen which continually 

 passes through. 



" In my early experiments I had found that the less vola- 

 tile hydro-carbons did not diffuse their vapour through hy- 

 drogen at ordinary temperatures, and hence it was necessary 

 to maintain an elevated degree by the application of foreign 



