Dr. Faraday has introduced an importvit arrangement for carrying, off the products of combustion in gut and oil lamps. Title arose out of a complaint, on the part of the members of the Athena:um Club, that time air of their library was vitiated and the binding of the Looks injured by the lamps then used. Dr. Faraday investigated the subject, and shortly afterwards communicated to the Institute of Civil Engineers the mods which he proposed to adopt for remedying the evil. In a paper communicated to this body ho adduced striking proof of the magnitude of the product remitting from combustion. " A pint of oil, when burned, produces a pint and a quarter of water, and a pound of gas mere than two and a half pones!' of water; time lnereaeo of weight being due to the absorption of oxygen from time nnuosphere, one part of hydrogen taking eight ports (by weight) of oxygen to form water. A London Argancl gas-lamp, in a closed Etiolate Indow, will produce in four hours two pints and a half of water ; a pound of oil also produces nearly three pounds of carbonic acid, and a pound of gas two and a half pounds of carbonio acid. For every cubic foot of gas burned, rather more than a cubic foot of carbonic acid is produced." As the water produced deadens the effect of the as the carbonic acid is very deleterious to the lungs, Dr. Faraday contrived a
mode of carrying both off without allowing them to mix with the air of the room. Air is admitted to feed the flame, nearly in the usual way ; but when the products of combustion have arrived at the top of the glass chimney, their progress is arrested by a covering of talc, and they are compelled to pass down between the chimney and another larger glass chimney concentric with it. The open apace between the two chimneys communicates with a pipe which is conducted in any convenient way into the open air ; the carbonic acid, aqueous vapour, smoke, anal other emanations from the flame have no means of escape except through this tube, and they are thus wholly cut off from con tact with the air of the room. The mode of carrying out the arrangement may bo varied in its details; but the general result is said to be that the light is brighter, the space around the lamp cooler, and the air of the room less vitiated than when common open burners are used.
Many other ingenious arrangements have since been adopted by different inventors; either to lessen the production of smoke, or to carry off the products of combustion without allowing them to mix, with the air of the room.