THE ELEMENTS OF THE ORBIT OF A SATELLITE. 
833 
corresponding to X=ijr would be 15 "2 centimeters from 0, and tlie point corresponding 
to X— 1 would be 17'4 centimeters from 0. 
We thus see that the degree of viscosity makes an enormous difference in the 
results. 
In the figure, portions of these further parts of the two curves for the variation of 
J are continued conjecturally by a line of dashes. 
The whole figure is to be read from left to right for a retrospective solution, and 
from right to left if we advance with the time. 
Fig. 7. 
Diagram to illustrate the motion of the proper planes of the moon and earth. 
