Astronomy. 17 
e in terrestrial magnetism as denoted by the diurnal 
=> 
sorption when the sun is strongest and diminishing absorption 
when the sun is weakest. 
On this account it seemed desirable to the authors to make a 
comparison of this kind between short-period Inequalities, since 
for these the length of period could not so easily be deemed suffi- 
tient to produce a great alteration of the above nature in the 
State of the atmosphere. : 
h 
tween solar and terrestrial Inequalities. e may take each indi- 
Vidual oscillation in sun-spot areas, and find the value of the ter- 
