Physiognomy of' the Momi's Surface. 45 



the otberhandjthe broad and long valleys of our mountain chains, 

 as of the Andes, the Alps, and the Himalaya, are quite unlike 

 any thing found in the moon, or the analogy at all events is a 

 most obscure one. Nearly all the forms of the earth's moun- 

 tains are changed by the action of water and atmospherical va- 

 riations, whilst these modifying agencies are probably wholly 

 wanting in the moon. 



We have still to make a few observations upon an appear- 

 ance in the moon, which presents a distant analogy to our rivers, 

 viz. the grooves and furrows (Ilille) which are so remarkable 

 and at the same time so difficult to recognise. They are long 

 and narrow hollows, sometimes straight or slightly arched, 

 and sometimes sinuous or crooked, which have been hitherto dis- 

 covered only in a small number of localities in the moon. Some- 

 times they extend from one small crater to another, and in other 

 cases, they appear to be isolated in the grey plains, terminating 

 in a manner in no way peculiar. Often they are stopped by 

 the mountains which they do not traverse. The grooves which 

 are situated near Higinus and Ariadeus, as well as that large 

 one which is found near Aristarchus, are those which may most 

 easily be discovered ; and in them we perceive, notwithstanding 

 their narrowness, a distinct trace of shadow. The numerous 

 grooves situated near Triesnecker, and the small ones in the 

 region of Posidonius are discovered with more difficulty. Their 

 whole number, as now established, is still limited ; although we 

 have discovered a certain number in regions where former ob- 

 servers never noticed them. Thus we have found four in the 

 south-west angle of the Mare humorum, one of which runs to- 

 wards Hippalus, and abuts to the north in the region of Agathar- 

 chides. The district near Triesnecker is still richer in fissures 

 which partially unite and again separate as in veins, and thus 

 form a particular system. Some of them are from two to three 

 miles in length, the majority are from ten to fifteen, and a small 

 number extend from twenty-five to thirty miles. We have 

 found none that exceed this maximum. 



The question now occurs, Are these grooves lunar rivers.? to 

 which we answer, that their resemblance to rivers is a very 

 slight one. They do not descend from the mountains, but ra- 

 ther cross their hollows. Those which are situated upon the 



