Brennett—Actinometric Observations of the Solar Eclipse. 373 
Equation (6) is the curve AHCD in fig. 1, and is ‘what the 
observed curve ABCD should have been to agree with the theory 
that the amount of light given out by the Sun during an eclipse 
is proportional to the fraction of his dise exposed. 
From these two equations, by division, we get 
