When the grass had grown abundant enough to furnish subsistence for their stock and draft animals, those who were ready with their outfit would begin to file out on the prairie trails converging upon the main Oregon road. After having traveled a day or two a halt was called by those in advance to await the coming up of others who proposed to undertake the same trip with themselves. The American instinct for organization would then assert itself, and there was occasion for its activity. They were in an Indian country. It was not wise to tempt the predatory propensities of the savages by too much straggling in their traveling or by too much unwariness in guarding their cattle and horses. In order to avoid molestation by prowling bands of Pawnees, Otoes, Cheyennes and Sioux, through whose ranges the trail east of the Rockies passed, it was necessary to travel in companies of some size and with such discipline as to be able to establish an effective guard at night and to make some demonstration of force when encountering considerable bands of Indian warriors. There was much economy, too, in bunching their several droves of loose stock into a single herd, in having a single lookout for selecting camping places, in the help that each would receive in case of accidents that all were liable to. Very essential, too, were organization and discipline when they came to a bank of a large stream across which their trail led. With the earlier migrations before printed guide books were available, organization was necessary to secure the services of a pilot. [Illustration: 11.—“DEVIL’S GATE,” Showing dam for leading out an irrigating ditch. ] The first large migrations—those of 1843 and 1844, and even of 1845—erred in attempting to go as one compact body. The difficulty of securing adequate grazing was much enhanced as the company increased in size. From this fact and the further fact that in case of a hitch or accident of any kind in a large company, many would be delayed who could be of no service in getting things fixed up for a fresh start, it resulted that twenty or thirty wagons were the maximum limit to the size of companies that did not chafe under their organization. In later years six or eight wagons were a normal number for a company. Even in the earlier migrations, when the Upper Sweetwater was reached and the danger from the Indians was measurably past, the large companies would divide up into sections. The earlier migrations, too, took precautions that no person attached himself to the train unless he was furnished with such resources as to rations and transportation that he would not likely become a common burden.