CIIEMI^.TRY. 211 



*' gas stoves," may be consumed without producing H^lit, except 

 of a pale-blue color, too iceble to ena!)lc one to see with. Thus, 

 the w^hole effect of the combustion is to generate heat, which is the 

 object aimed at, w^hile the same coal gas, not mingled witi) air 

 until burned, will furnish liglit as well as heat. lL*nee we may 

 have the same amount of chemical action, at one time resulting in 

 heat alone, and under other conditions evolving luminous as well 

 as calorific rays, fiu-nishing a beautiful illustration of the correla- 

 tion of forces. "When oxygen and pure hydrogen unite they pro- 

 duce a most intense heat, over 14,000° F., and ranking next to 

 the galvanic current, yet the flame is almost invisible by daylight. 

 If, however, any solid body be held in it, even though non-com- 

 bustible, as lime, magnesia, etc., the imponderable force heat is 

 transmuted into light. 



By this mode of illumination, therefore, one of the objectionable 

 features in the use of coal gas — namely, the oppressive heat, 

 both in private residences, churches, and theatres (especially in 

 the summer season) — is in great part removed. 



0. This light does not vitiate the air as much as other lights of 

 equal brillianc}', — a sanitary condition too often neglected. Ordi- 

 nary artificial lights injure the atmosphere in two ways, — by re- 

 moving its oxygen, which is so essential for respiration, and l)y 

 producing carbonic-acid gas. A single 6-feet burner will yield as 

 much of this poisonous gas as 8 or 9 persons would expire in quie^ 

 tude, while it would abstract more oxvgen from the surroundino; 

 air than they would absorb in the same time. 



In this new lamp, oxygen is supplied in sufficient quantity to 

 consume the coal gas, — the atmosphere is not taxed to aid the 

 combustion, — and as the consumption of carburetted hydrogen in 

 this burner is from one-sixteenth to one-twentieth for the same 

 illuminating power, there will be proportionally less of impurities 

 resulting from its use. From our gas flames a portion of uncon- 

 sumed carbon always arises, which darkens the ceilings, soils the 

 walls and the furniture. No such smoke escapes from this light, 

 for the combustion is complete. 



For out-of-door illumination it has an additional advantage, 

 that by no possibilit}' can it be " blown out." The chemial action 

 is so intense that it cannot be extinguished in the Stormiest 

 weather; and even if the two gases be shut off for a minute or 

 two the glowing pencil of magnesia will relight them when they 

 are again turned on. The preparation of this oxygen differs 

 markedly from the making of coal gas ; there is no ill odor attend- 

 ing it, and, if hydrogen should be employed, as proposed by the 

 same ingenious French chemists, their method of fabricating it by 

 heating fine anthracite coal dust, peat, or other carbonaceous sub- 

 stance, mingled with hydrate of lime, would furnish us with means 

 for illuminating and heating, without contaminating the atmos- 

 phere of our crowded cities with the nauseating and unwholesome 

 gases with which we are now annoj'cd. 



In point of economy, by the use of oxygen and carburetted 

 hydrogen combined, with the same amount of light, the public 

 may save from 30 to 40 per cent, in money, allowing large profits 



