4 A. ASHE ON A NEW INCANDESCENT LIGHT 



m eans perfect, its advantages are sufficient to warrant further 

 im provement at the hands of those who can do so. 



In conclusion I would suggest that attention be given to some 

 method of overcoming the drawback of the uneven- surface of 

 the roll, although this is very much less apparent in the field of 

 view than when the ordinary plain mantle is used. 



Note. — Since the above was written, I have pleasure in adding 

 that Mr. Traviss has succeeded in preparing- discs of Thoria 

 which give a perfectly even illuminated surface, and are less 

 "fragile than mantles. They can be used for critical purposes, 

 and he has by this improvement quite overcome the weak points 

 in my lamp. 



Journ. Quekett Microscopical Club, Ser. 2, 7ol. XIV., No. 8i, April 1919. 



