“The precession of the equinoxes,” said Mr Foster, “will gradually ameliorate the physical state of our planet, till the ecliptic shall again coincide with the equator, and the equal diffusion of light and heat over the whole surface of the earth typify the equal and happy existence of man, who will then have attained the final step of pure and perfect intelligence.”

“It is by no means clear,” said Mr Jenkison, “that the axis of the earth was ever perpendicular to the plane of its orbit, or that it ever will be so.  Explosion and convulsion are necessary to the maintenance of either hypothesis:  for La Place has demonstrated, that the precession of the equinoxes is only a secular equation of a very long period, which, of course, proves nothing either on one side or the other.”

They now emerged, by a winding ascent, from the vale of Llanberris, and after some little time arrived at Bedd Gelert.  Proceeding through the sublimely romantic pass of Aberglaslynn, their road led along the edge of Traeth Mawr, a vast arm of the sea, which they then beheld in all the magnificence of the flowing tide.  Another five miles brought them to the embankment, which has since been completed, and which, by connecting the two counties of Meirionnydd and Caernarvon, excludes the sea from an extensive tract.  The embankment, which was carried on at the same time from both the opposite coasts, was then very nearly meeting in the centre.  They walked to the extremity of that part of it which was thrown out from the Caernarvonshire shore.  The tide was now ebbing:  it had filled the vast basin within, forming a lake about five miles in length and more than one in breadth.  As they looked upwards with their backs to the open sea, they beheld a scene which no other in this country can parallel, and which the admirers of the magnificence of nature will ever remember with regret, whatever consolation may be derived from the probable utility of the works which have excluded the waters from their ancient receptacle.  Vast rocks and precipices, intersected with little torrents, formed the barrier on the left:  on the right, the triple summit of Moelwyn reared its majestic boundary:  in the depth was that sea of mountains, the wild and stormy outline of the Snowdonian chain, with the giant Wyddfa towering in the midst.  The mountain-frame remains unchanged, unchangeable:  but the liquid mirror it enclosed is gone.

The tide ebbed with rapidity:  the waters within, retained by the embankment, poured through its two points an impetuous cataract, curling and boiling in innumerable eddies, and making a tumultuous melody admirably in unison with the surrounding scene.  The three philosophers looked on in silence; and at length unwillingly turned away, and proceeded to the little town of Tremadoc, which is built on land recovered in a similar manner from the sea.  After inspecting the manufactories, and refreshing themselves at the inn on a cold saddle of mutton and a bottle of sherry, they retraced their steps towards Headlong Hall, commenting as they went on the various objects they had seen.