So IN STARRY REALMS. 



circumstances, the moon's distance and movement, that it 

 was attracted by the earth with a force of the same 

 description as that by which the same globe attracted the 

 apple ; the difference being that the intensity of the force 

 becomes weaker the greater the distance of the attracted 

 body from the earth. In fact, the attraction of the earth 

 on a ton of matter at the distance of the moon would be 

 withstood by an exertion not greater than that which 

 would suffice to sustain about three-quarters of a pound at 

 the surface of the earth. I do not, however, now enter 

 further into the subject, but in my little volume of lectures 

 entitled " Star Land," I have endeavoured to explain the 

 movement of the moon under the action of gravitation in 

 as simple a manner as possible. 



The moon is entirely dependent upon the light from the 

 sun for her illumination. This is now well known, but 

 the ancients seem to have had the impression that the 

 moon must be self-luminous, at all events to a certain 

 extent. Nor can it be denied that a plausible reason for 

 such a supposition may be offered. The simplest con- 

 siderations suffice to show that the phases of the moon, 

 those interesting changes by which its light increases from 

 the faint crescent up to the half moon and then to the full 

 moon, are due to the aspects under which the sun-illu- 

 minated hemisphere is turned towards us. There is, 

 however, one condition in which the moon seems to present 

 a justification for the belief that it contains some intrinsic 

 light. In the early stages, while our satellite is still a 

 crescent, the larger part of its disc can be seen to glimmer 

 with a pale ashy light. This could not have come directly 

 from the sun, and hence it was supposed that it was 



