Our encampment was within a few miles of the place where the road crosses to the North fork, and various reasons led me to divide my party at this point. The North fork was the principal object of my survey; but I was desirous to ascend the South branch, with a view of obtaining some astronomical positions, and determining the mouths of its tributaries as far as St. Vrain's fort, estimated to be some two hundred miles farther up the river, and near to Long's Peak. There I hoped to obtain some mules, which I found would be necessary to relieve my horses. In a military point of view, I was desirous to form some opinion of the country relative to the establishment of posts on a line connecting the settlements with the south pass of the Rocky Mountains, by way of the Arkansas and the South and Laramie forks of the Platte. Crossing the country northwestwardly from St. Vrain's fort, to the American Company's fort at the mouth of the Laramie, would give me some acquaintance with the affluents which head-in the mountain between the two; I therefore determined to set out the next morning, accompanied by four men--Maxwell, Bernier, Ayot, and Basil Lajeunesse. Our Cheyennes, whose village lay up this river, also decided to accompany us. The party I left in charge of Clement Lambert, with orders to cross to the North fork; and at some convenient place, near to the _Coulee des Frenes_, make a cache of every thing not absolutely necessary to the further progress of our expedition. From this point, using the most guarded precaution in his march through the country, he was to proceed to the American Company's fort at the mouth of the Laramie's fork, and await my arrival, which would be prior to the 16th, as on that and the following night would occur some occultations which I was desirous to obtain at that place. 5th.--Before breakfast all was ready. We had one led horse in addition to those we rode, and a pack-mule, destined to carry our instruments, provisions, and baggage; the last two articles not being of great weight. The instruments consisted of a sextant, artificial horizon, &c., a barometer, spy-glass, and compass. The chronometer I of course kept on my person. I had ordered the cook to put up for us some flour, coffee, and sugar, and our rifles were to furnish the rest. One blanket, in addition to his saddle and saddle blanket, furnished the materials for each man's bed, and every one was provided with a change of linen. All were armed with rifles or double-barrelled guns; and, in addition to these, Maxwell and myself were furnished with excellent pistols. Thus accoutred, we took a parting breakfast with our friends; and set forth.