No. UW. Incandescent Gas Lamp and Glass Flask. For the purpose 

 of illumination we supply an incandescent glass lamp mounted on a brass 

 stand with ordinary burner and Jena glass chimney together with two reserve 

 mantles and in combination with this lamp a glass flask on a special stand. 



Xo. 200. Glass Flask on Stand. This flask is also supplied separately. 

 It has a diameter of about 15 cm (6 in.). It is most efficient when placed midway 

 between lamp and microscope at a distance of 15 cm from both. 



Xo. 201. Collective Lens with Iris-diaphragm. This apparatus consists 

 of a simple collective lens (of about 125 mm [4 7 / g in.] length) with an iris- 

 diaphragm attached to its mount. It stands upon a massive foot and the lens 

 is adjustable in height. This appliance helps, not only to produce a better image 

 of the source of light, but also to confine the illuminated portion of the field 

 within sharply defined limits. It is for this reason that it is so well adapted for 

 illumination by means of the vertical illuminator (see pp. 34 and 35). 



Spectroscopes. 



Nos. 202 to 204. BROWNING'S Hand-Spectroscopes. 



This form of spectroscope is fitted with a set of AMICI prisms of great 

 dispersion and is principally intended for the examination of large objects as, 

 for instance, troughs filled with liquid matter. 



For particulars of other spectroscopes consult the special prospectuses 

 issued by our Department of Optical Measuring Instruments. 



Qail 



