Page:Proceedings of the Royal Society of London Vol 1.djvu/100

Rh found them consisting of the same elements as the earthy globules of the stone from Benares.

From a collective view of the contents of this paper, we may now reasonably infer, that all the substances here mentioned, not except- ing the native irons from Siberia and South America, and some from Bohemia and Senegal, have a manifest relation with each other. Mr. Howard recapitulates these analogies ; and, with a view to the further investigation of the subject, closes his paper with the follow- ing queries :—lst. Have not all fallen stones, and what are called Native Irons, the same origin P—2nd. Are all or any the produce of meteors ?—and 3dly. Adverting to the circumstance of the Yorkshire stone having fallen during a serene sky, might not this stone have formed a meteor in regions too elevated to be Within the reach of our observation?

The observations described in the ﬁrst part of this paper relate to the magnitude, the colour, the disc, and the atmosphere of the two moving stars lately discovered by Mr. Piazzi and Dr. Olbers, to which they have assigned the names of Ceres and Pallas; and also to the question, whether they bs attended by any satellites. Their magnitudes were determined by means of a comparison of thm'r re- ﬂected images with a lucid spot of a disc micrometer placed at con- siderable distances. The results of many observations were, that the diameter of Ceres does not subtend an angle of more than 0"“40, or in actual length only 1624- miles; and that the diameter of Pallas can hardly mwsure more than between 71 and 72 miles. The colour of these bodies was ruddy, and in one instance Pallas was of a dusky white. Their discs were never of a well deﬁned planetary appear— ance; and as to their atmospheres or comas, the greatest extent of that attending Ceres was in one instance about two diameters beyond its disc; in another instance the whole had a cometary appearance; or when viewed most accurately, it bore a great resemblance to a small, much compressed, but ill-deﬁned planetary nebula. Pallas never exhibited more than a faint haziness. As to satellites, it was inferred previous to the observations, that bodies of such very small dimensions could hardly contain a quantity of matter suﬂicient for the retention of secondary bodies ; and in fact the several appearances that seemed to denote the existence of such attendants, were on more careful inspection found to be fallacious.

In the second part of the paper Dr. Herschel enters into an inquiry concerning the nature of these new stars, particularly as to the question whether they be planets or comets. And in order to proceed upon certain grounds, he previously enumerates certain criteria by which the heavenly bodies may be properly distinguished. These, as to the planets, are seven in number. 1. Those till lately discovered are all