400 April 5, 
Chase. ] 
one per cent. from Hansen’s estimate, and only one twenty-fifth of one 
per cent. from the mean of all the estimates, may, perhaps, be reasonably 
regarded as entitled to the greatest weight. The narrow compass within 
which they are all embraced, and the close approximation to the mean of 
the best astronomical computations, may be seen in the following table : 
Newcomb (mean of two estimates)................. 92, 266,000 
TERRESTRIAL ROTATION (upper limit).......... 91,965,500 
LUNAR DISTANCE 91,813,400 
LUNAB MONTH. cee 91,798,500 
MEAN OF MECHANICAL ESTIMATES............ 91,767,736 
Stone (Mean OL two Gstimates) ase we ee 91,728,500 
PloMSOHee are ee, oe, ee Ee ee 91,672,000 
HYDROGEN EXPLOSION (ly. 22. 30. 91,665,320 
Mean of. Astronomical Estimates.................... 91,636,800 
VELOCITY OF LIGHTS...) ss 91,595,960 
EVERIGE  . ace eo gis conde 6 eth oi 91,329,000 
WHO CG. itn cp che ac tee pL ous 5 6 eee es 91,186, 000 
Is it possible that there can be anything deceptive in these figures,— 
that any bias of unsuspected prejudice may have blinded me, or that I 
have been misled by mere fortuitous resemblances? The question 
whether there is not some conception of force which will unify centrifugal 
and centripetal, luminous, thermal, and gravitating action, is continually 
recurring ; the accordance of Faraday’s ‘‘lines of force’’ with lines of 
perfect fluidity, and the fundamental equation of oscillation, favor an 
affirmative answer; the increasing popularity of the theory that matter 
is nothing but force, prepares the way for every conceivable approxima- 
tion and identification of molar and molecular laws. 
If the undulations of light have any influence upon the gravity of 
bodies, the velocity of light being nearly uniform, its influence should 
tend to communicate a velocity as nearly like its own as gravity and. 
' inertia will allow, a tendency which is presumably most manifest in the 
most tenuous forms of matter. The gravitating velocity, 
Ta I Me i : 
————1/24gh KX — ——1/2mh, being a maximum. when 75—/ and hocm 
i Ve J 5 D > 
r+h rh 
it does not seem unreasonable to look for analogies between the extreme 
excursions of planets, satellites and gases, or between times, ve.ccities, 
and living forces, in the direction of that maximum. 
GENERAL RELATION OF AURORAS TO RAINFALL. 
By Prrny Harte CHase. 
(Read before the American Philosophical Society, April 5th, 1872.) 
In order to ascertain if the parallelism, which I have pointed out be- 
tween the daily rainfall and the frequency of auroras, can be traced in the 
annual curves, [ have constructed the following table of normals, from 
data furnished by Lovering’s Catalogue of Auroras, and Loomis’s Meteor- 
sian 
