

THE JOURNAL 'f^ 



OF THE '•"s,.^ ^^ 



A NEW INCANDESCENT UGHT FOR MICROSCOPICAL 

 ILLUMINATION. 



By a. Ashe, Esq., F.K.M.S. 



(Read October 8th, 1918.) 

 FiGTjRE IN Text. 



The Welsbach gas light has not been accepted with, such favour 

 by microscopists as an illuminant as might have been expected 

 from such a powerful brilliant and white light. The reason, 

 however, is very obvious. An image of the coarse structure 

 of the web of the mantle being projected into the field of view 

 destroys all evenness of illumination, whilst for high-power 

 critical work the comparatively enormous area of the source of 

 light is an additional and serious drawback to its use. If these 

 disadvantages could be entirely overcome it is certain that we 

 should then have a most welcome addition to our very limited 

 means of illumination. 



When the Welsbach light was first introduced, I carried out 

 a number of experiments for the purpose of making a smaller 

 and more concentrated light than that given by the upright 

 mantle, the small inverted ones now so common not having 

 been then introduced. To this end I constructed some miniature 



JouRN. Q. M. C, Series II.— No. 84. 1 



