CARBURETTED HYDROGEN. 



LIGHT CARBURETTED HYDROGEN. 



What is u kt ' ^ ESCRIPTION - Light carburetted 



carburctted hydrogen is a colorless, inodorous, in- 

 Whcre does it flammable gas, about half as heavy as 

 occur? a j r j ts mo iecule contains two atoms of 



carbon to four of hydrogen. It is produced in ponds and 

 marshes, by the decomposition of vegetable matter under 

 water, as will be more fully explained in Part III. From 

 this circumstance it is also called marsh gas. Mixed 

 with other gases, it issues from fissures in coal mines, 

 forming the fire damp, formerly so much dreaded, on ac- 

 count of its explosive properties. As coal is of vegeta- 

 ble origin, the gas of the mines which proceeds from 

 it is also traceable to the vegetable world. In some 

 districts, and more particularly in regions where 

 borings are made for salt, it issues from the earth in 

 sufficient quantity to form the fuel which is required 

 to boil down the brine, or even to illuminate villages. 



How is it pre- 549. PREPARATION. - An 



pared? impure, light, carburetted hy- 



drogen, is obtained from wood, by simple 



heating. For this purpose, saw-dust, or 



bits of shavings are heated in a test-tube. 



The gas may be burned in a jet as fast as 



formed. The product thus obtained is 



not pure, but mixed with olefiant, and 



other gases, which make the flame more 



luminous. The pure gas, may be made 



from strong vinegar, (acetic acid,) by the agency of 



heat and potash, as will be explained in the latter part 



of this work. 



