Management of Light in Illumination. 141 



lamp. It has a circular foot d, and it ends above at the 

 moulding z, which belongs to it, and forms what may 

 be considered as its brim. Into the opening of the 

 tube c, the lower extremity of the tube b enters at 

 about one inch ; and it is firmly fixed in it by means of 

 a contrivance similar to that used for fixing a bayonet 

 to its musket. 



About one inch and a half above the lower extremity 

 of the tube b, this tube is perforated by a circular row 

 of air-holes, which goes quite round it. These holes 

 are concealed by the hoop /i, which is fastened to the 

 tube b by means of three vertical projections, made of 

 pieces of wire soldered to the tube at equal distances 

 from each other. The hoop being afterwards soldered 

 to the ends of these wires, it is supported by them in 

 its place, and the air passing between the inside of the 

 hoop and the outside of the tube enters the air-holes. 



The use of this hoop is to screen the air-holes, and 

 prevent the flame of the lamp from being disturbed by 

 sudden gusts of wind ; and the mouldings i and k are 

 placed above and below this hoop for the same pur- 

 pose. 



/ is a button which is used for moving a rack (con- 

 cealed in the inside of the tube b\ which serves for 

 elevating and lowering the wick, e is the handle of the 

 lamp, which projects horizontally from the side of the 

 circular reservoir a. It is hollow, and about six inches 

 in length ; and it serves at the same time as a handle 

 and as a secondary reservoir for containing the oil. 

 For want of room, it is represented in the figure as 

 being broken off. 



/is the stopper which closes the opening by which 

 oil is poured into the lamp. 



