495 
Mr. Ivory on the astronomical refractions. 
This Table of refractions has been constructed merely with 
the view of comparing the theory contained in the Paper with 
observation. The elements are precisely the same as those 
of the French Table in all other respects excepting the quan- 
tity f, which is assumed equal to from the exact manner 
in which this value seems to represent terrestrial observa- 
tions. But it would be more satisfactory to determine the 
same quantity by the comparison of many observed refrac- 
tions at low altitudes, between the distances of 85° and 88® 
from the zenith ; and by this means a Table might be con- 
structed that would be deserving of greater confidence. 
J. IVORY. 
