Let us now reason from our principles, in order to see how far the present appearances of things would naturally result from those wasting causes acting upon a mass of granite, of a given basis and of sufficient height, during a space of time which is unlimited.

We are to suppose our mass of granite without any structure except that of the veins and cutters, formed by the contraction of the solid mass in cooling.  Now, those separations will naturally give direction to the operation of the wasting causes, whether we consider these as chymical or mechanical.  Hollow tracts would thus be formed in the solid mass; in those hollow ways would flow the water, carrying the detached portions of the rock; and those hard materials, by their attrition upon the solid mass, would more and more increase the channels in which they move.  Thus there would be early formed a system of valleys in this rock, and among those valleys a number of central points, or summits over which no running water would carry hard materials to operate upon the solid rock over which it flows.

Here therefore, in the nature of things, is placed the rudiments of our needles, those colossal pyramids which acquire height gradually as the valleys widen, and whose apices may arrive at an angle of a certain degree of acuteness.  But what a waste of rock to have formed all those needles which we find rising from the icy valleys round Mount Blanc!

Upon the supposition that this had been the origin of those pyramidal mountains, it must be evident, that there is a ne plus ultra of acuteness to which the apex of a pyramid would in time arrive; and that then the decaying summit would tumble by the lump alternately, and regain the acuteness of its point.  Now, if this be the case, although we cannot see the process, which is too slow for human observation, we should actually find them in all the stages of this progress.  But this is precisely the state in which the summits of those mountains are to be found.  M. de Saussure gives a view of one of those pyramids, which will serve to illustrate this subject in the most perfect manner.  It is from the Montanvert that this object is to be perceived. (Voyages dans les Alpes, vol. 2.).

These high peaks of solid rock demonstrate the manner in which those enormous masses of mountains are degraded, and also the means which are employed by nature for that purpose; but this scene, however well represented, is too far removed, in its appearance, from the ordinary mountains of this earth, to satisfy the doubts of every reader or to generalise a principle which must be universal in the system of this earth.  We therefore have occasion for a mean, by which the extreme of those alpine summits shall be generalised or connected with our low inclined plains; and, on this occasion, I will give M. de Saussure’s most excellent description of the Breven.  Nothing can better suit our present purpose than the subject of this natural history; and I am persuaded that most readers will be better informed by the description of this naturalist, than they would be by their own observation.