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that a river, which, previous to its disappearance, is in itself so considerable, and in many placesrapid and impetuous, would re-appear with some degree of velocity; but, on the contrary, Icould scarcely discern the direction of its course; for, except some trifling bubbles and eddies(occasioned no doubt by the confined particles of air which disengage themselves from the water,and the resistance it experiences among the craggy rocks in the interior of the mountain), itascends, from its subterraneous channel, with a most surprising placidness, unaccountable, unlessupon the following principle:—It may, I presume, be attributed to the form of the channel, whichis most probably that of a siphon, with the leg or end, where the Rhone re-appears, more verticalthan the other;—a conjecture which seems the more probable, as it in a great measure accountsfor the total loss of a variety of objects, such as dogs, pigs, large pieces of timber, &c.which have at different times been thrown in, by way of experiment. But, what is more singular,this stagnant and almost motionless current re-assumes, at a short distance from where it emergesfrom the subterraneous passage, the whole of its original rapidity, and by again becoming consi-derable, continues navigable until it reaches the Mediterranean sea *. But, with a hope of throw-ing more light on this subject, I have annexed two views, which represent the loss and re-appear-ance of this noble river. (See N os VIII. and IX.)

Gratified with exploring this extraordinary place, I by no means regretted the time and troubleI had now bestowed on it, since the day yet sufficed to reach Geneva. I therefore made the bestof my way toVanchi.

As soon as I had left this village, which is about eight miles from the fort of> Cluse, I began,imperceptibly, to turn the head of the Jura , leaving the mountains of Credo behind. But herethe valley contracts so considerably, that in several places there is scarcely room for the course ofthe Rhone; and the road, which is better than could be expected, is oftentimes cut in the mainrock.

I then proceeded through the romantic little villages of Grezin, Lia, and Lougaretta, renderedparticularly picturesque by their situation, being situated at the very foot of the Jura , and on thebanks of the Rhone, where its impetuous waters fall, with tremendous noise, into a frightfulabyss which they have formed contiguous to those villages.

At Lougaretta I first began to discover clearly the abrupt spiry head of the Jura , and the directionof its strata, which are there nearly perpendicular to the horizon. This singularity is observablein this long range of mountains, as far as to the neighbourhood of Colonge, a village three milesbeyond Ecluse; and they likewise stretch to those of the head of the Vouaches, another chain ofmountains which skirt the left banks of the Rhone, and which have a similar direction in theirstrata, also the same thickness, and fossils like those contained in the Jura . What adds verygreatly to the abpve singularity is, that these may be considered as almost the only places in thisvast range where the strata exhibit that abruptness and direction, being every-where else nearlyparallel to the horizon : besides, several of the mountains belonging to these chains have in manyparts an extreme acclivity, which extends almost to their summit.

This analogy and similarity of direction, still more conspicuous in those which screen thedefile of Cluse, have at all times excited my curiosity, and led me to believe that they originallyformed one and the same chain, it having invariably appeared tome that it really was so. I alsoconceive that the effect of separation has been produced by some sudden convulsion of theearth in that part of the secondary chain of the Alps (most probably at a time less distant thanappears at first), of which the violence and extent was such as to entirely sever those mountainsfrom top to bottom which now border the defile,—and, if so, naturally caused the cavities andirregularities at present exhibited in their strata. These cavities have doubtless been since increasedby the current of the lake of Geneva, which was probably more considerable at that epocha thannow, and by the succession of torrents fed by rains, &c. which sweep after each other from thetop of those mountains, and throw themselves into the Rhone, as I shall hereafter endeavour toillustrate.

The fort of Cluse has nothing remarkable except its situation, which is particularly interesting,'beintr as though stuck to the bare rock of the Jura , which shelves over a part of its fortifications

* Perhaps tbe circumstances here mentioned, respecting the loss and re-appearance of the Rhone, may induce some tobelieve, that, in one part of its subterraneous passage, .it must filtrate through some very porous stratum, or pass through theinterstices of immense beds of broken rocks.

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