270 



Mr. G. H. Darwin. 



[Mar. 18, 



Fig. 3 illustrates the changes of inclination of the satellite's orbit, 

 and may be interpreted in the same way as fig. 2. It appears from the 

 part of the figure for which x is negative, that if the revolution of the 

 satellite be negative, and the rotation of the planet positive, but the 



Fig. 3. 



Diagram for Inclination of Satellite's Orbit. — First case. 



m. of m. of planetary rotation greater than that of orbital motion,, 

 then, as the satellite approaches the planet, the inclination of the orbit 

 increases, or zero inclination is dynamically unstable. In every other 

 case the inclination will decrease, or zero inclination is dynamically 

 stable. 



This result undergoes an important modification when a second 

 satellite is introduced, as will appear in the unpublished paper. 



Fig. 4 shows a similar curve for the eccentricity of the orbit. The 

 variations of the eccentricity are very much larger than than those of 

 the obliquity and inclination, so that it was here necessary to draw the 



