I 38 ] 

 CHAP. V. 



GASS LIGHTS. 



SECTION I. 



Introductory Remarks. 



I. HB term gass or gas (from the German gheist or spirit, whence 

 our own ghost, ghostly, aghast, ghastly) is used in modern che. 

 inistry, to express all those aerial fluids, whether produced by 

 chemical experiments or evolved in natural processes, which are 

 not condensible by the cold of our atmosphere, and which differ 

 from atmospheric air, which is indeed a compound, consisting of 

 three distinct gasses, as we have already observed in a former part 

 of this work. 



Of these fluids, some are inflammable, others not. Of the for. 

 mer, the chief are hydrogen, and the gass emitted from phosphorus. 

 It is possible, however, that phosphorus itself is a compound of 

 hydrogen and oxygen, with a peculiar base, and consequently, 

 that hydrogen is the inflammable principle in this instance. 

 Be this as it may, phosphorus, concerning which we shall treat 

 presently, is by no means so easily procured as hydrogen, and 

 hence, it is this last which is ordinarily had recourse to, in pro. 

 cesses for the production of light or inflammation from gasseous 

 substances. 



We have observed in the preceding chapter on AEROSTATION, 

 that the earlier name for hydrogen was inflammable air, a name 

 indeed derived from this very principle of inflammability ; its mo. 

 dern name was given it by Lavoisier, from its being found to be 

 the chief constituent part or principle of water, which is now well 

 known to b<- a compound, consisting of a larger portion of hydro, 

 gen, or inflammable air, and a smaller of oxygen, concerning which 

 our readers may turn to the chapter on the constituent principles 

 of WATER. 



Hydrogen gass enters very largely into all animal, most vegeta. 

 ble, and a great variety of mineral compositions. It hence fre. 



