C 339 3 
XV. Account of the Changes that have happened, during the last 
Twenty-five Tears , in the relative Situation of Double-stars ; 
with an Investigation of the Cause to which they are owing. 
By William Herschel, LL. D. F. R. S. 
Read June g, 1803. 
In the Remarks on the Construction of the Heavens, contained 
in my last Paper on this subject,* I have divided the various 
objects which astronomy has hitherto brought to our view, into 
twelve classes. The first comprehends insulated stars. 
As the solar system presents us with all the particulars that 
may be Known, respecting the arrangement of the various su- 
bordinate celestial bodies that are under the influence of stars 
which I have called insulated, such as planets and satellites, 
asteroids and comets, I shall here say but little on that subject. 
It will, however, not be amiss to remark, that the late addition 
of two new celestial bodies, has undoubtedly enlarged our know- 
ledge of the construction of the system of insulated stars. 
Whatever may be the nature of these two new bodies, we know 
that they move in regular elliptical orbits round the sun. It is 
not in the least material whether we call them asteroids, as I 
have proposed; or planetoids, as an eminent astronomer, in a 
letter to me, suggested ; or whether we admit them at once into 
the class of our old seven large planets. In the latter case, 
however, we must recollect, that if we would speak with precision, 
• See Phil. Trans, for 1802, p. 477. 
