226 T. C. CHAMBERLIN THE GREATER EARTH 



found it to be 9,241 miles. The difference is so trivial as to make the 

 results mutually confirmatory. Of course, in all such computations there 

 is a margin of doubt. The mass of the earth is not accurately deter- 

 mined, nor is the mass of the moon, nor are any of the basal data strictly 

 accurate. 



