“Not being able to discover any more of these animals, we returned to camp.  Here, in turning over some of the baggage, we caught a rat somewhat larger than the common European rat, and of a lighter color; the body and outer parts of the legs and head of a light lead color; the inner side of the legs, as well as the belly, feet, and ears, white; the ears are not covered with hair, and are much larger than those of the common rat; the toes also are longer; the eyes are black and prominent, the whiskers very long and full; the tail is rather longer than the body, and covered with fine fur and hair of the same size with that on the back, which is very close, short, and silky in its texture.  This was the first we had met, although its nests are very frequent in the cliffs of rocks and hollow trees, where we also found large quantities of the shells and seed of the prickly-pear.”

The queer rat discovered by Lewis and Clark was then unknown to science.  It is now known in the Far West as the pack-rat.  It lives in holes and crevices of the rocks, and it subsists on the shells and seeds of the prickly pear, which is usually abundant in the hunting grounds of the little animal.  The explorers were now constantly in full view of the Rocky Mountain, on which, however, their present title had not then been conferred.  Under date of July 2, the journal says:—­

“The mosquitoes are uncommonly troublesome.  The wind was again high from the southwest.  These winds are in fact always the coldest and most violent which we experience, and the hypothesis which we have formed on that subject is, that the air, coming in contact with the Snowy Mountains, immediately becomes chilled and condensed, and being thus rendered heavier than the air below, it descends into the rarefied air below, or into the vacuum formed by the constant action of the sun on the open unsheltered plains.  The clouds rise suddenly near these mountains, and distribute their contents partially over the neighboring plains.  The same cloud will discharge hail alone in one part, hail and rain in another, and rain only in a third, all within the space of a few miles; while at the same time there is snow falling on the mountains to the southeast of us.  There is at present no snow on those mountains; that which covered them on our arrival, as well as that which has since fallen, having disappeared.  The mountains to the north and northwest of us are still entirely covered with snow; indeed, there has been no perceptible diminution of it since we first saw them, which induces a belief either that the clouds prevailing at this season do not reach their summits or that they deposit their snow only.  They glisten with great beauty when the sun shines on them in a particular direction, and most probably from this glittering appearance have derived the name of the Shining Mountains.”

A mysterious noise, heard by the party, here engaged their attention, as it did years afterwards the attention of other explorers.  The journal says:—­