Gruithuisefi's City m the Moon. 219 



the other the first meridian. E. of this point we notice an 

 imperfect ring, Sommering, touching the equator : N. of this 

 is a somewhat similar object, the Schroter of B. and M., forming* 

 the principal feature in " a labyrinthine mass, the complete 

 disentangling of which could scarcely be successfully accom- 

 plished with the most powerful telescope. The countless 

 multitude of hills which fill this landscape appears, even in 

 favourable circumstances, almost like a mere fine luminous 

 dust." Most of the elevations, however, show connection in 

 chains, affecting a general parallelism with the tolerably distinct 

 boundaries of the district, which consists exclusively of the 

 minutest and most difficult groups. There is no great amount 

 of elevation, especially for the Moon : some points in the outer 

 border of the mass may reach 2600 f. The interior hills are 

 very difficult of measurement : F, central, and by far the 

 highest, may lie 2500 f. above a valley 9 miles E. The majority 

 of the eminences range from 1000 down to 130 or even 70 f. 

 The least visible of them lie eastward ; but they are probably 

 steep-sided, as, even when the detail is confused by too high 

 an illumination, they never give the impression of a plain, 

 notwithstanding their grey colour ; and this tone may be due 

 to the great multitude of minute and separately undistinguish- 

 able shadows. Craters are rare amongst them. Such is the 

 account of B. and M., who add in a note, that notwithstanding* 

 their especial care, which they hope a comparison of their 

 Map with the sky will prove, they could never perceive the 

 slightest traces of the fortress-like ramparts which had been 

 so much paraded for a length of time. Lohrmann, they add, 

 had met with no more success ; his figure, indeed, was very 

 unlike theirs, but under the circumstances this could not be 

 matter of surprise. L.'s design is certainly not merely very 

 dissimilar, but poor in detail, and his complaints of difficulty 

 are evidently very sincere. 



If we now turn to the origin of these remarks, it is as 

 follows. 1822, July 12, Gruithuisen discovered in the region 

 before us what he considered to be a colossal structure con- 

 sisting of regular and obviously artificial ramparts, to which he 

 gave the name of Schroter (subsequently transferred by B. and 

 M., when they could not find his object, to the crater so 

 designated in our diagram). Its extent was about 23 miles 

 each way, but it was very dark, and situated in one of the 

 darkest parts of the Moon, and was visible only on the termi- 

 nator. Its general outline accurately faced the points of the 

 compass, there being a central ridge from N". to S., from 

 which branched off at an ano-le of 45° on either side, a number 

 of parallel walls, like the the veins of an alder or rose-leaf, run- 

 ning respectively S.E. and S.W.. Those running S.E. flattened 



