OASS LIGHTS. 89 



quently set at liberty by fermentations, or spontaneous decompo- 

 sitions, is thrown forth from bogs and marshes, when, from a 

 spark of natural electric fire, or some other accidental cause, it is 

 ofVn seen burning under the form of ignes futui, or zsill-o'-the- 

 whisps ; is occasionally kindled by similar cause-, in coal or me. 

 taltic mines, with dreadful explosions and mischief, of which we 

 have already given various examples in the preceding part of this 

 work ; and is collected at times from substances that possess it in 

 the largest abundance, for purposesof ECONOMICAL ILLUMINATION. 

 It is under this last character that we are alone to consider it 

 upon the present occasion. As the general principle of inflam- 

 mations, all inflammable bodies necessarily contain it in a greater or 

 less degree: such more especially as metals, alkoliols, oils, and 

 bitumens or coals of every kind, and it constitutes the fine blue or 

 purest part of the flame emitted from a candle or a fire, when 

 made with good round coals, that melt into pitch. Of these dif- 

 ferent substances, coals or bitumens may be obtained in the largest 

 abundance, and with the greatest ease j and it is hence by a dis- 

 tillation of these, that the gass is usually procured, which is em. 

 ployed in gass lights. The means by which this is accomplished, 

 the expence attending the process, and the great advantage of 

 having recourse to it in extensive manufactories, or other places 

 where large bodies or lengths of light are absolutely necessary, we 

 shall now proceed to explain from a very valuable paper cum. 

 municated to the Royal Society, by the ingenious artist and phi- 

 losopher, who may justly be regarded as the inventor of the prac. 

 tical application of the light of hydrogen gass to useful purposes. 



[Edit or. 



SECTION II. 



Application of the Gass from Coal to economical Purposes. 

 By Mr. William Murdoch. 



THE facts and results intended to be communicated in this pa. 

 per, are founded upon observations made, during the present 

 winter, at the cotton manufactory of Messrs. Philips and Lee at 

 Manchester, where the light obtained by the combustion of the 

 gass from coal is used upon a very large scale; the apparatus for 

 its production and application having been prepared by me at the 

 works of Messrs. Boulton, Watt, and Co. at Soho. 



