Marsh, who is remembered today for his contributions to ecology in his book, Man and nature, was appointed by president Zachary Taylor  United States minister resident in the Ottoman Empire from 1849-1854. There he undoubtedly became familiar with camels, and believed that there would be economic and other benefits of introducing the camel into the United States. His book covers a broad range of issues relating to the camel, including breeds, diet, diseases, temperament and training. Marsh also includes a chapter on the military uses of the camel, which he felt was perfectly suited for the warfare of his day. According to Marsh, the camel "is a much less timid animal than the horse or mule." He also believed that riding a camel offered a better range of vision, because it is two feet higher than the horse. Digital facsimile from the Internet Archive at this link.