As this modest treatise does not pretend to be a learned one, and as the author is not a professional scholar, no further attempt will be made to claim the production of the science of astronomy as an invention. To pursue the subject further would be merely to enter a discussion as to the meaning, both original and derived, of the word invention. The author, however, cannot escape the conclusion that, no matter what may be the literally correct meaning of the word, the mental acts performed by the originators of the science of astronomy were like the mental acts performed by the inventors of mechanical appliances, and exerted a similar influence on history. That is, he believes that the men who brought into being the science of astronomy and the men who brought into being the bow and arrow, first saw pictures on the mental retina of some things actual yet vague and formless, and then constructed entities from them. He believes also that the creation of the bow and arrow, and the creation of the science of astronomy constituted actual and similar stepping-stones on which the race rose toward a higher civilization. In default of any definition of the word invention, which precludes its application to the origination of a science, theory, religion or formulated school of thought, the author begs permission so to use it, in indicating the influence on history of the novel creations which, according to this meaning of the word, have been inventions. The influence on history of the invention of the science of astronomy has been so great that we cannot estimate its greatness. On it the whole science of navigation rests. Without it, the science and the art of navigation could not exist, no ships could cross the ocean from one port to another, except by accident, and the lands that are separated by the ocean would still rest in complete ignorance of each other. This world would not be a world, but only a widely separated number of barbarian countries; most of them as ignorant of even the existence of the others as in the days before Columbus. Following the invention of astronomy, or as it was first called, Astrology, the imaginative and practically constructive intellects of the Babylonians naturally led them to invent the sun-dial for indicating the time during the day, and the water-clock for indicating it during the night. Another invention, doubtless brought into being by the study of the movements of the heavenly bodies, was the duodecimal system of notation, of which the base was twelve. In accordance with this system, the Babylonians divided the Zodiac into twelve equal parts or "signs"; divided the year into nearly equal months, that corresponded approximately to the length of a lunar month; divided a day and a night into twelve equal parts or hours; divided an hour in sixty (12 x 5) equal parts or minutes, and divided a minute into sixty (12 x 5) equal parts or seconds.