GASEOUS SUNLIGHT. 141 



XXV. GASEOUS SUNLIOHT. 



NATURAL GAS ITS WONDERS AND ITS GEOLOGY. 



ILLUMINATING and Heating Gas is one of the products of 

 the earth. Its escape is a geological phenomenon. Its pres- 

 sure, its volume, its composition, its permanence, are facts 

 , from which the geologist deduces past conditions in the world's 

 history. It was stated in the last talk that its origin is un- 

 doubtedly similar to that of oil, and that oil is chiefly the 

 product of the distillation of shales charged with vegetable 

 matter probably ancient sea-weeds which grew in veritable 

 " Sargosso Seas." As sun-light is the active agent in vegeta- 

 ble growth, a stem or a leaf is simply a body of transformed 

 sun-light. When imbedded in the rocks it is strictly and lit- 

 erally fossil sun-light. In petroleum, ancient sun-light is pre- 

 served in liquid form ; in natural gas it is gaseous. 



The escape of burning gas from the earth has been ob- 

 served for ages. For more than fifty years, the gas escaping 

 with the brine from the wells of the Kanawha Valley, West 

 Virginia, has been employed in the evaporation of the brine. 

 It has long been utilized in some salt mines where it escapes 

 through crevices. In a similar way, it enters coal mines, and 

 is known to miners as fire damp, since, mixed with a certain 

 proportion of atmospheric air, it becomes violently explosive. 

 The Chinese have for centuries, employed natural gas for 

 lighting and heating. On the Cumberland, in Kentucky, 

 gas accumulates in underground reservoirs, and the elastic 

 pressure is sometimes attended by explosions, constituting 

 earthquakes of local extent, and lending some plausibility to 

 the ancient theory of those phenomena. At Fredonia, New 

 York, are gas emissions which have attracted attention for 

 many years, and have long been utilized for lighting and 

 heating. A gas spring was discovered here in 1821. The 

 gas at that time accumulated was used for lighting a mill and 

 several stores. It was also introduced into a few public build- 

 ings, and was brought to the attention of Lafayette when he 



