ACCESSORY INSTRUMENTS. 



151 



quite fall or nearly empty, the light is perfectly uniform, 

 which is not the case with the Cambridge lamp before men- 

 tioned, unless it be constructed upon the plan of Mr. Spencer, 



described in page 157. The author 

 for many years has used a emaU 

 French fountain lamp, fig. 107; it 

 has an exceedingly small wick, always 

 burns well, and gives an excellent 

 light, and the consumption of oil being 

 small, it is advantageous in an econo- 

 mical point of view. There are many 

 other little contrivances in this French 

 lamp, which deserve a separate 

 description. The stem does not pass 

 through the reservoir, as in the Cam- 

 bridge lamp, but through a square 

 piece of brass having two holes, one 

 on either side of that through which 

 the stem passes ; these holes commu- 

 nicate with the reservoir, and the oU 

 flows through them into the tube 

 supporting the burner. By this ar- 

 rangement the reservoir is placed on one side of the stem and 

 the burner on the other, and the two balance each other. 

 The gallery supporting the chimney is provided with ten 

 fin-like pieces of soft brass, about three-quarters of an inch in 

 length ; these stand up in a circle and press against the sides 

 of the chimney and keep it steady ; they can be bent either 

 inwards or outwards to fit any chimney that wiU go into the 

 lower part of the gallery. The cup at the bottom of the 

 burner, to hold the superfluous oil, is ingeniously furnished 

 with a funnel-shaped mouth just above the screw, by which it 

 is attached to the burner ; the funnel receives aU the oil that 

 runs down the outside of the burner, and in it are two holes 

 by which the oil may escape into the cup. This contrivance 

 prevents the oil from flowing over the outside of the cup, 

 which by these means is kept clean. 



Some French lamps have a rack and pinion for raising the 



Fig. 107. 



