Of prehistoric times we have, of course, no written record; and we have but the most general means of estimating how many millenniums ago man first had his being. Geological considerations indicate a beginning so indefinitely and exceedingly remote that the imagination may lose itself in speculations as to his mode of living during those forever-hidden centuries that dragged along, before man had advanced so far in his progress toward civilization as to make and use the rude utensils which the researches of antiquarians have revealed. Inasmuch as the most important employment of man from his first breath until his last has always been the struggle to preserve his life; inasmuch as the endeavor of primeval man to defend himself against wild beasts must have been extremely bitter (for many were larger and stronger than he), and inasmuch as man eventually achieved the mastery over them, one seems forced to conclude that man overcame wild beasts by employing some means to assist his bodily strength, and that probably his first invention was a weapon. The first evidences of man's achievements that we have are rude implements of stone and flint, evidently shaped by some force guided by some intelligence;--doubtless the force of human hands, guided by the intelligence of human minds. Many such have been found in caves and gravel-beds over all the world. They were rough and crude, and indicate a rough and crude but nevertheless actual stage of civilization. Some call this the Old Stone Age and others call it the Early Stone Age. Besides stone and flint, bones, horns and tusks were used. Among the implements made were daggers, fish-hooks, needles, awls and heads of arrows and harpoons. One of the most interesting revelations of those rude and immeasurably ancient implements is the fact that man, even in those times, possessed the artistic sense; for on some of them can be seen rough but clear engravings of natural objects, and even of wild animals. [Illustration: Carvings in Ivory (1 and 3-7) and in Stone of Cavern Walls (2), made by the Hunters of the Middle Stone Age]