Smithsonian Report, 1911.—Heaton. 
{7 Stones 27 
ueing examined, 
LM ILL 
. 4, * 
414 
Focussing /;/ 
Lenses,’ 
2. CONSTRUCTION OF THE HERBERT SMITH REFRACTOMETER. 
es or, sia 7 
3. THE DICHROSCOPE. 
PLATE 1. 
