140 Management of Light in Illumination. 



being covered and protected by its glass chimney, 

 burns so steadily that it is not in the least deranged 

 either by the wind or in being moved about from place 

 to place ; and the flame of this lamp is so immovably 

 fixed in the axis of its chimney, by the ascending cur- 

 rent of air, that it does not quit it, even when the 

 chimney is considerably inclined, so that the flame 

 very seldom touches the glass. 



This lamp has one quality which no other ever pos- 

 sessed before in the same perfection. It may be made 

 to furnish any quantity of light required, from that of 

 the smallest bed-chamber lamp or feeblest taper to 

 that furnished by three or four candles all burning 

 together; and these alternate variations in the quan- 

 tities of light emitted by it may be repeated at pleas- 

 ure, without any trouble, merely by turning a button 

 which moves a rack that is concealed in the body of 

 the lamp, or rather in the column on which it is 

 placed. 



I shall first endeavour to give an idea of the general 

 form of this lamp, and shall then proceed to describe 

 its various parts more particularly. 



In order to render these descriptions more satisfac- 

 tory, I have given a figure of the lamp (Plate VI., Fig. 2) 

 drawn to a scale of half its real size, a, Fig. 2, is a cir- 

 cular reservoir which surrounds the upper end of the 

 vertical tube b, in the axis of which the burner is 

 placed. 



The end of the burner appears above the circular 

 reservoir, and its flame is confined in the glass chim- 

 ney g, which, for want of room, is represented broken 

 off, just above the point of the flame. 



The vertical tube c is the stand which supports the 



