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CHARLES B. WARRING. 91 
ing into the sun, which, reaching down to the least, causes 
the water to stay in the pail which the school boy whirls 
around his head, and often spreads destruction by the 
bursting of a too rapidly revolving wheel. 
This is the so-called ‘‘ centrifugal force.”’ Its philos- 
“ophy Ineed not explain. It is sufficient for my pur- 
pose that all recognize it. 
As all know, if the boy ceases to revolve the pail, its 
contents fall. Ifthe wheel is at rest, the centrifugal 
force no longer acts. It is the result of motion around a 
centre, always coming with such movement. 
Hence if our solar system and all its fellow systems 
are revolving around some grand center, the danger of 
all tumbling together like an ill-constructed arch is re- 
moved, and from unceasing movement comes stability. 
The mind so revolts from any scheme in nature that 
seems to bear marks of imperfection that for this reason 
alone we would infer the reality of such a revolution. 
There is, however, very satisfactory evidence that our 
own system is in rapid motion, and if ours, then others. 
It has long been known as the result of careful meas- 
urements that the stars in the northern hemisphere are 
apparently separating while those in the southern seem 
to be drawing closer together. This cannot be due to a 
real movement for it is impossible to conceive of them as 
all moving at once, those in the north from a certain 
point,and thosein the south towardsa northern point 180° 
away, keeping, as it were, all in step like soldiers to 
music. If real, the movement would lack the uniformity 
it now exhibits. 
The only explanation conceivable is that the two 
effects are optical illusions, the same in principle as when 
one stands on a train of cars in motion. If he is on the rear 
platform, the tracks, fences, trees and, in short every- 
thing that he passes, appear to approach each other. 
The track grows narrower, the fences move towards the 
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