James White, 3d U.S.Artillery, fifteen soldiers and "as many rugged mountain men" as escort.

He had succeeded in navigating with the General Jesup as far up the river as El Dorado Canyon, about sixty-eight miles below the mouth of the Virgin--that is, he had gone clear through Black Canyon and thus holds the record for the first ascent of the Colorado with a steamboat to the limit of steamboat navigation.

This feat he executed with the avowed purpose of "getting ahead" of Lieutenant Ives who had arrived December 1, 1857, at Robinson's Landing at the mouth of the river, bringing an iron steamboat (as described in the next chapter) under orders from the War Department to explore the Colorado as far as possible.
* Beale used camels on this expedition and considered them a success.
Johnson had been aware of his presence and intentions having been sent down from Fort Yuma with two steamboats to transport certain supplies from the vessel which brought Lieutenant Ives.

He had reached the schooner December 17th.

On January 2, 1858, he left Fort Yuma on his northward run knowing that Ives could not follow him until the steamboat brought in sections could be completed.
Ives had entirely ignored Johnson, as well as Johnson's skill in navigating this river, and also his powerful steamboats.