445 
Mr. Ivory on the astronomical refractions. 
ct ( I -1- 
we shall have 
By means of this formula Kramp has found, 
A^= 0.200865, 
= 0.160253, 
A (s) = 0.132935, 
&c. 
And with these values the horizontal refraction, in an atmos- 
phere of uniform temperature, will come out equal to 
In this case, therefore, the refractions, at the horizon greatly 
exceed the truth, although at the zenith they agree with 
observation. 
It is therefore certain that if we augment m, by successively 
putting m = 2, m = 3, &c., we shall at length find an atmo- 
sphere that will agree with nature both at the zenith and the 
horizon. But if we reflect that there must be an intimate 
connection between the quantity of the refractions and the 
gradation of heat in the atmosphere, we shall probably be 
spared some repetitions of the same operations, by determin- 
ing m so as to satisfy Equation ( B ) . Now we have 
2254" . 5. 
m -f 1 
s 
consequently, 
and hence m = 4. 
