He was responsible for exploring several viable routes to the Pacific across the Rockies in the 1840s. He made an unsuccessful bid for the presidency in 1856, losing to James Buchanan.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。