United States or South Africa ? Vote for the TOP Country of the Week !
With regard to their distribution on the lunar surface; they are found in almost every region, but perhaps not so frequently on the surface of the Maria as elsewhere, though, as in the case of the Triesnecker and other systems, they often abound in the neighbourhood of disturbed regions in these plains, and in many cases along their margins, as, for example, the Gassendi-Mersenius and the Sabine-Ritter groups.
A deep rill-like valley winds round its eastern glacis, commencing on the S. at a small circular enclosure standing at the end of a spur from the wall; and, after crossing a ridge W. of a bright little crater on the N. of the formation, apparently joins the most easterly cleft of the Triesnecker system.
A cleft traverses the N. side of the floor of Rhaeticus, and extends across the plain on the E. as far as the N. side of Reaumur. TRIESNECKER. Apart from being the centre of one of the most remarkable rill-systems on the moon, this ring-plain, though only about 14 miles in diameter, is an object especially worthy of examination under every phase.
The observer will find much to interest him in the great, irregular, and much-broken mountain ring called Julius Cæsar, as well as in the ring mountains, Godin, Agrippa, and Triesnecker. The last named, besides presenting magnificent shadows when the sunlight falls aslant upon it, is the center of a complicated system of rills, some of which can be traced with our five-inch glass.
The keen-sighted and very imaginative Gruithuisen believed that in some instances they represent roads cut through interminable forests, and in others the dried-up beds of once mighty rivers. His description of the Triesnecker rill-system reads like a page from a geographical primer.
The intricate network of rills on the west of Triesnecker, when observed with a low power, reminds one of the wrinkles on the rind of an orange or on the skin of a withered apple. Gruithuisen, describing the rill-traversed region between Agrippa and Hyginus, says that "it has quite the look of a Dutch canal map."
Published maps are all more or less defective in their representations of them, especially as regards that portion of the system lying N. of Triesnecker. HYGINUS. A deep depression, rather less than 4 miles across, with a low rim of varying altitude, having a crater on its N. edge. This formation is remarkable for the great cleft which traverses it, discovered by Schroter in 1788.
After weighing, however, all that can be said "for and against," the hypothesis of change seems to be the most probable. UKERT. This bright crater, 14 miles in diameter, situated in the region N.E. of Triesnecker, is surrounded by a very complicated arrangement of mountains; and on the N. and W. is flanked by other enclosures. It has a distinct central mountain.
It is also probably joined to the Triesnecker system by one or more branches E. of Hyginus. On May 27, 1877, Dr. Hermann Klein of Cologne discovered, with a 5 1/2 inch Plosel dialyte telescope, a dark apparent depression without a rim in the Mare Vaporum, a few miles N.W. of Hyginus, which, from twelve years' acquaintance with the region, he was certain had not been visible during that period.
Word Of The Day