at the total solar Eclipse in 1882. 
47 
round until its edges abut, forms the reflecting surface of the 45° 
mirror is specified by the following construction. 
On a sheet of paper, or on the silvered sheet of metal, describe 
from the same centre two circles with radii of 7 07 and 
Fig. 5. Geometrical construction of Keflector used. 
7 ’07 - 2‘83 = 4*24 inches respectively. The circumference of 
the greater circle is 44*44 inches. The upper rim of the 45° 
reflector has a radius of 5 inches, therefore its circumference 
