Page:Philosophical Transactions - Volume 004.djvu/238

 munication pass into the very Channels of the little rivers Lers, Fresqueil, Aude; Monsieur Riquet maketh his Channel pass, as much as he can, in the adjacent Plains, leaving the ancient Channels of those Rivers to serve for receiving and carrying away the great and frequent inundations of waters, and thereby securing the new Channel from the danger of being inconvenienced by them.

The highest place of the whole Channel was well enough known, which was to be the Point, call'd the Point of Division or Separation. Nature herself sufficiently pointed at it by the Spring of Grave, which partly runs towards the Ocean, and partly towards the Mediterranean: and 'tis near this place, where the great Bason is made to receive the waters, that are to run both tides of the Channel. But this water being not near sufficient, it was necessary to find out others, that might be high enough to fall into the said Bason, and abounding enough to keep it always full, and to furnish for the Sluces of those two parts of the great Channel.

It appear'd also, that this plenty of waters could not be had but from the Black Mountain, distant enough from it; but it did nornot [sic] appear, how this could be effected. In short, 'tis this wherein the greatest difficulty of the whole work did consist. For we must know, that there are many Springs issuing from the higher part of that Mountain, and that among the rest there are Five great ones, which make as many small rivers, that are never dryed up, and run along the hillocks of this Mountain, and fall together into the river Fresqueil; but so far above the said Point of Separation, that that remoteness would render them absolutely useless, it not being possible to make them re-mount. Wherefore to make them serve for this purpose, it was necessary to interrupt their natural course from North to South, and to give them a contrary one, from East to West, by digging a Conduit for them cross the Mountain, through places, which are all steep rocks and horrid precipices. There was then a necessity to make those five rivers run, the first into the second, and the second into the third, fourth and fifth, and to re-unite them all in the Deriving Channel, which at last carries them to the Point of Separation for the end above-mentioned.