LAMPS 



ironmongers, -who disputed his right by any improvements to infringe the profits of 

 their chartered vocation. ' This invention,' to quote a description of the lamp pub- 



1309 



1311 



1312 



lished some years ago, ' embraces so many improvements upon the common lamp, and 

 has become so general throughout Europe, that it may be justly ranked amongst the 

 greatest discoveries of the age. As a substitute for the candle, it has the advantage 

 of great economy and convenience, with much greater brilliancy ; and for the purpose 

 of producing heat, it is an important instrument in the hands of the chemist. We 

 may, with some propriety,' continues this authority, ' compare the common lamp and 

 the candle to fire made in the open air, without any forced method of supplying it 

 with oxygen ; while the Argand lamp may be compared to a fire in a furnace, in 

 which a rapid supply of oxygen is furnished by the velocity of the ascending current. 

 This, however, is not the only advantage of this valuable invention. It is obvious 

 that, if the combustible vapour occupies a considerable area, the oxygen of the atmo- 

 sphere cannot combine with the vapour in the middle part of the ascending column. 

 The outside, therefore, is the only part which enters into combustion ; the middle 

 constituting smoke. This evil is obviated in the Argand lamp, by directing a current 

 of atmospheric air through the flame, which, instead of being raised from a solid wick, 

 is produced from a circular one, which surrounds the tube through which the air 

 ascends. 



The mechanism of the Argand burner, in its improved state, will be clearly 

 understood from the annexed figures and explanation, which apply equally to each 

 description of the lamps hereafter described. 



A, fig. 1313, is a brass tube, about 3J inches in length, and 1 J inch wide ; within 

 this tube is placed another, B, which is soldered fast inside by the flange at c : the 

 space between these tubes contains the oil surrounding the wick, and which, being 

 freely admitted from the reservoir by the side pipes D E, rises in the tubular space, 

 either to a height corresponding with its level in the reservoir, or at least so as to 

 maintain the wick in a state of constant saturation. The tube B is of considerable 

 thickness, having a spiral groove cut about it from top to bottom ; p is a metallic 

 ring made to slip over the tube B, it contains a short pin inside, which fits exactly 

 into the spiral groove just mentioned ; a is the circular woven cotton wick, the lower 

 end of which is drawn tight upon the neck of the ring ; H is a copper tube, with a slit 

 nearly from top to bottom ; it admits the ring F, and being dropped over the inner 

 tube B, exactly fits the inside of the wider tube A, by means of a narrow rim near the 



