That they are beyond comparison smaller than any of the seven planets cannot be questioned, when a telescope that will show a diameter of 1 of a second of a degree, leaves it undecided whether the disk we perceive is a real or a spurious one.
A distinct magnifying power, of more than 5 or 6 hundred, has been applied to Ceres, Pallas, and Juno, but has either left us in the dark, or at least has not fully removed every doubt upon this subject.
The criterion of the apertures of the mirror, on account of the smallness of these objects, has been as little successful; and every method we have tried has ended in proving their resemblance to small stars.
It will appear, that when I used the name asteroid to denote the condition of Ceres and Pallas, the definition I then gave of this term will equally express the nature of Juno, which, by its similar situation between Mars and Jupiter, as well as by the smallness of its disk, added to the considerable inclination and excentricity of its orbit, departs from the general condition of planets. The propriety therefore of using the same appellation for the lately discovered celestial body cannot be doubted.
Had Juno presented us with a link of a chain, uniting it to those great bodies, whose rank in the solar system I have also defined, by some approximation of a motion in the zodiac, or by a magnitude not very different from a planetary one, it might have been an inducement for us to suspend our judg-
- See Phil. Trans, for 1802, p. 229, line 10.
- Ibid, page 224, line 5 of the same Paper.