It must be remembered, however, in respect to all such statements relating to the efficiency of the bow and arrow, that the force with which an arrow can be thrown depends not upon any independent action of the bow, but altogether upon the strength of the man who draws it. The bow, in straightening itself for the propulsion of the arrow, expends only the force which the man has imparted to it by bending it; so that the real power by which the arrow is propelled is, after all, the muscular strength of the archer. It is true, a great deal depends on the qualities of the bow, and also on the skill of the man in using it, to make all this muscular strength effective. With a poor bow, or with unskillful management, a great deal of it would be wasted. But with the best possible bow, and with the most consummate skill of the archer, it is the strength of the archer's arm which throws the arrow, after all. It is very different in this respect with a bullet thrown by the force of gunpowder from the barrel of a gun. The force in this case is the explosive force of the powder, and the bullet is thrown to the same distance whether it is a very weak man or a very strong man that pulls the trigger. But to return to the Monguls. All the information which we can obtain in respect to the condition of the people before the time of Genghis Khan comes to us from the reports of travelers who, either as merchants, or as embassadors from caliphs or kings, made long journeys into these distant regions, and have left records, more or less complete, of their adventures, and accounts of what they saw, in writings which have been preserved by the learned men of the East. It is very doubtful how far these accounts are to be believed. One of these travelers, a learned man named Salam, who made a journey far into the interior of Asia by order of the Calif Mohammed Amin Billah, some time before the reign of Genghis Khan, says that, among other objects of research and investigation which occupied his mind, he was directed to ascertain the truth in respect to the two famous nations Gog and Magog, or, as they are designated in his account, Yagog and Magog. The story that had been told of these two nations by the Arabian writers, and which was extensively believed, was, that the people of Yagog were of the ordinary size of men, but those of Magog were only about two feet high. These people had made war upon the neighboring nations, and had destroyed many cities and towns, but had at last been overpowered and shut up in prison.