1 78 HERSCHEL AND HIS WORK 



them run along its very minute arms " at the rate of 

 9 or 10 miles a second ! He was looking from 

 Windsor across a gulf in space about nine hundred 

 millions of miles in width. It was a romance of the 

 heavens one of many. 



On ascertaining that his great telescope was not 

 required for these observations on the ring and moons 

 of Saturn, he " made ten new object specula and 

 fourteen small plain ones for his 7 - feet reflector, 

 having already found that the maximum of distinct- 

 ness might be much easier obtained than where large 

 apertures are concerned." During his long-continued 

 watch of Saturn he saw sometimes a northern belt on 

 the body of the planet, sometimes two belts at the 

 equator. In a couple of days the entry in his journal 

 became " a bright belt over a dark one " ; and, nine 

 days later, " one dark and one very faint white belt." 

 The last entry he quotes in 1790 is, "The bright belt 

 close to the ring and two dark equatorial belts." 

 These belts would be about one hundred thousand 

 miles in length: what were they? Similar belts or 

 bands had long been seen and studied on the planet 

 Jupiter. It was agreed among observers that they 

 were probably due to cloudy masses floating in 

 Jupiter's atmosphere. If the same explanation hold 

 for the belts of Saturn, the changes, seen on them 

 by Herschel, would be explained by "a very con- 

 siderable atmosphere," in which they take place. He 

 not only adopted this conclusion, but confirmed it by 

 another observation. When the two nearest of the 

 moons the two he discovered in 1789 came, in their 

 progress round the planet, to the edge of the disc, 

 they did not disappear at once, but continued "to 



