about half past one
`` Shall I ever realize the absurdity of my entering into an argument with a scientist ! '' But this time the Projectile , though advancing northward with a pretty uniform velocity , had neither gained nor lost in its nearness to the lunar disc . Each moment altering the character of the fleeting landscape beneath them , the travellers , as may well be imagined , never thought of taking an instant 's repose . At about half past one , looking to their right on the west , they saw the summits of another mountain ; Barbican , consulting his map , recognized _ Eratosthenes _ . This was a ring mountain , about 33 miles in diameter , having , like _ Copernicus _ , a crater of immense profundity containing central cones . Whilst they were directing their glasses towards its gloomy depths , Barbican mentioned to his friends Kepler 's strange idea regarding the formation of these ring mountains . `` They must have been constructed , '' he said , `` by mortal hands . ''