width between the two parts.[1] The black disc or belt was not in the middle of the ring's breadth. "It is a zone of considerable breadth," which was always seen permanently in the same place. As it was not, what some seem to have supposed, the shadow of a vast range of mountains on the ring's surface, he resolved to wait till the planet came into a position which would enable him to see the stars through the black belt, if it really were a division in the ring, a window, as it were, through which he could look out into space beyond. He does not appear to have been successful in this quest, and it has not been done by others. That there were two unequal rings,[2] separated by this black line, he was satisfied. They were bright rings, but the inner was the brighter of the two. Near the outer edge of the outer ring, he observed and figured "a black list," fainter than the dividing gulf. He did not consider it a division in the outer ring, but it is now a recognised feature, traceable all round. Herschel also
- ↑ The dimensions of Saturn and his rings are, according to Proctor (Encyc. Brit., "Astronomy," p. 783)—
Diameter of the planet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70,136
miles Between planet and "crape" ring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9,760" Breadth of "crape" ring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8,660" "of inner bright ring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17,605" "of division between bright rings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,680" "of outer bright ring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9,625" The diameter of the ring system is thus about 165,000 miles. Herschel made it about (204,883) 205,000 miles in diameter. He believed that the breadth of the ring is to the space between the ring and the planet as 5 to 4 (Phil. Trans., 1806, p. 463). If the "crape" be left out of account in measuring the ring, the proportion is about 5 to 3⋅2 (Phil. Trans. for 1792). He estimates the vacant space between the outer and inner rings at nearly 2513 miles.
- ↑ In the proportion of 805 to 280, while the space between was reckoned 115.
