Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 3, 1802).djvu/80

62] LAM The last patent we shall notice, vas granted in 1800 to Messrs. "White and Smethl'Rst, for their i?nproved lamp-htrner. —Thewhole is modestly called an improvement on the burner of the common Ar- gand lamp ; and the objeet of which is, to attbrd a more free and plenti- ful supply of oil to the ignited part of the wick ; so that it will burn better, rec]uire less frequent snuff- ing, and answer well, even Avith oil of an inferior quality. These advantages are obtamed simply, by leaving a larger- than the usual space betA^een the two tubes, Avith- in which the wick is placed. Yet it is necessary to contradl such space towards the top, in order that the burnt crust or cinder may be more conveniently removed ; gn objeA which may be effected by applying a ring or piece of metal, conically or odierwise formed, so as to reduce the space in the upper part of the lamp to the usual di- iuensions. The advantages of Messrs. "White and Smethurst's im- provement, are: 1. That the in- convenience hitherto complained of, respecting the mode of cleaning and dressing the lamps, is thus re- inoved ; as, upon their plan, the capillary tubes of the cotton wick are prevented from being at any time obstruded by the viscid na- ture of the oil, while its ascent is promoted by such capillary attrac- tion. 2. The quantity of oil con- sumed by these improved lamps is, by the patentees, stated to be less, in tire proportion of at least four to iive. 3. One of the most import- ant advantages thence derived, is, tJiat of the wick being rendered lit to burn common whale, or seal- oils, which are sold at about half the price of the best spermaceti oil. LAM the only inflammable fluid hitherfd- used in Argand's lamps ; while the former produce an equal de-* gree of light. We have alread}' pointed out (in vol. i. p. 432, article Candle) the superior utility of lamps, especialijr for sedentary and studious persons; but as the light emitted by them is frequently too vivid for weak, or irritable eyes, "we would recom- mend the use of a small screen, which should be proportionate to the disk of the flame, and be placed at one side of the light, in order to shade it from the reader's eye, without excluding its effe&. from others, or darkening the room. Such a contrivance is equally sim- ple and useful : it may consist either of paper, or taffety, slightly gummed ; and, being easily tokied and carried in the pocket, is far superior to the common screens. We c;mnot conclude this article, without pointing out another cir- cumstance in which lamps are su- perior to candles, namely, their cheapness. From experiments made some years since, AAith the ex- press view of ascertaining the ex- pence of burning chamber-oil, it appears that a common taper- lamp, with eight cotton tlireads in the wick, consumed in one hour tWo P-irts, or about one-third of an ounce of spermaceti oil, which at that time cost 2s. 6d. per gallon ; so that the expcnce of burning for 12 hours, amounted to 4 57 Ear- things, or about l^ of a penny. The light emitted by such lamp, was as clear and bright as that 3'ielded by candles, which run from eight to ten in the pound. — Subse- quent trials were made with M. Argand's lamp > the result of which was, that the latter will con- tinue to burn three bouis for the value