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ANNUAL REPORT SMITHSONIAN INSTITUTION, 1950 



Observations of this kind evidently connect the motion of the moon, 

 the distance of the moon, and distances on the earth in a very inter- 

 esting way, which may refine our knowledge concerning our own globe, 

 as well as concerning its satellite, the moon. 



Figure 6. — Schematic picture showing measurement of distances on the earth by 

 contact determinations at an eclipse. If the contacts are observed when the 

 cone of the lunar shadow points at Ei and E2, the distance on the earth corrected 

 for the rotation of the earth in the time interval between the two observations 

 is E'lEa. 



It is typical for science to proceed in successive approximations 

 toward increased knowledge. New connections between observed 

 phenomena oifer the possibility of penetrating the secrets of nature 

 in greater and greater detail. This is true also for the wonderful 

 mechanism of our solar system. Even if the astronomer nowadays is 

 often carried by his ambition to study distant galaxies, it is still true 

 that some of the deepest secrets of nature that can come within the 

 working field of the astronomer lie hidden within the limits of our 

 own solar system, and, above all, in the sun itself, the patient donor 

 of all good gifts to our planet and to mankind. 



