THE FOECEPS, ETC. 67 



the stand. This carries an argand burner B j a metal cone c rises to 

 the level of the burner, and is about one-eighth of an inch from its 

 outer margin. 



This arrangement gives a bright cylindrical flame. The bottom of 

 the stage A is covered with wire-gauze, to cut off irregular currents of 

 air, and thus secures a steady flame. Over the burner is placed a 

 Leblond's blue glass chimney d. This corrects the colour of the flame 

 to a certain extent ; but it is still further rectified by a disc of bluish- 

 black neutral-tint glass e, fitted in a tube f, attached obliquely to the 

 shield G. G is a half-cylinder of metal, which serves to shield the eyes 

 from all extraneous light, but may be rotated on the stage a by aid of 

 the ivory knot h, when the full light from the flame is desired. A 

 metallic reflector i, fixed on its supports, so as to be parallel to e, con- 

 centrates the light. By the combination of the two glasses d and e, 

 the yellow rays of the flame are absorbed, and the arrangement affords 

 a soft white light, which may be still further improved by receiving 

 the rays on a concave mirror, backed with plaster-of-Paris, l ; and 

 where a very strong light is required, a condensing lens should be 

 interposed, as shown in the cut, between the lamp and the mirror of 

 the microscope. By removing the shield G, and bringing the shade Ji 

 over the burner, it may be used as a reading-lamp. A retort ring n 

 supports a water-bath o, or a wrought-iron plate p, 6 inches by 21 inches, 

 both used in mounting objects. The stop-cock Q gives the means of 

 regulating the flame. The screw R clamps the lamp-head at any height 

 desired. The lamp may be attached to any gas-supply by vulcanised 

 India-rubber tubing. 



Forceps. — For holding minute objects, such as parts of plants or 

 insects, to be examined either as transparent or opaque objects, the 

 most useful is represented by fig. 45, and consists of a piece of steel 



<r3fl^=^i^q~7r:, — I Q 



W^ 



fig. 45. 



wire, about three inches long, which slides through a small tube, con- 

 nected to a stout pin by means of a cradle-joint j to one end of the 

 wire is attached a pair of blades, fitting closely together by their own 

 elasticity, but which, for the reception of any object, may be separated 



