and Laboratory Methods. 



2665 



When using the camera lucida, it is necessary to have a mirror placed so as 

 to show a fairly strong light upon the paper and the pencil point. A piece of 

 silvered glass three or four inches square is large enough. Such a mirror can 

 be held by an ordinary ring stand, as shown in Figs. 1 and 2. 



These globes are being used in our laboratory both for research work and 



Fig. 2. 



for ordinary class work.^ For class work, three or four globes are used at a table 

 and receive their light from a single Welsbach lamp. 



We believe that such light is not only equal to the best daylight but is, in 

 many cases, superior. Charles J. Chamberlain. 



^The globe and mounting which we are now using were made according to our directions by 

 Dr. Wm. H. Knap, Powers building, 1 56 Wabash avenue, Chicago. Dr. Knap should be ad- 

 dressed for further particulars. 



