344 & r - Herschel’s Account of the Changes that have happened 
motions, and the ratio of the distances of the bodies be given 
quantities, a supposition in which we admit their concurrence, 
may explain the phenomena of a double star, but can never be 
probable. 
Motions of the three Bodies. 
No. 5. If we admit different motions in every one of the 
three bodies, O, a, x , and if the velocities and directions of the 
motions, as well as the relative distances of the three bodies are 
determined, an hypothesis which admits the existence of such 
motions and situations, may resolve the phenomena of a double 
star, but cannot have any pretension to probability. 
The compass of this Paper will not allow me to give the ob- 
servations of my double stars at full length; I shall therefore, 
in the examination of every one of them, only state those parti- 
culars which will be required for the purpose of investigating 
the cause of the changes that have taken place, either in the 
distance, or angle of position, of the two stars of which the 
double star is composed. 
As the arguments in the case of most of these stars will be 
nearly the same, it may be expected, that the first two or three 
which are to be examined will take up a considerable space; 
and the number of double stars, in which I have already ascer- 
tained a change, amounting to more than fifty, it will not be 
possible to give them all in one paper ; I shall therefore confine 
the present one to a moderate length, and leave it open for a 
continuation at a future opportunity. 
