22 A.C. Twining on Occultations by the Moon and Planets. 
The relations of illumination to magnifying power, when visibility 
. is maintained. 
A feebly illuminated area obliterates a point close to it, al- 
though of a much stronger light. We desire to know the laws 
which govern such an effect. Again, with the telescope, visi- 
bility depends both upon light and magnifying power. By in- 
i t wo 
lar,—yet the indicated results, although with some evident lati- 
tude, appear to be unmistakeable. 
| : 
elding of the eord and 
of this apparatus was a want of equable 
Se : fi om he a se fl 
e ligh ld often move fitfully, not 
