hand, young societies which are active are likely to show an interest in science before they make any headway in the production of the fine arts. The appearance of art requires an economic condition which produces luxury, and a social condition which will stimulate the emotional life; while science requires economic progress which will stimulate the useful arts and a social condition which will emancipate the mind from the domination of the past.
The discussion thus far has been confined to the origin and effects of positive knowledge in general; it now remains to consider the more detailed effects upon progress of the separate sciences. The origin, or at least the early development of the sciences, may in almost every case be traced to an attempt to improve the arts or to obtain some specific object, and the chief service to society of these sciences has usually been in solving those very problems which gave them their origin. A brief account therefore of the beginnings of the leading sciences will open the way to a discussion of their effects upon social progress.
Astronomy was one of the oldest sciences to take definite form, originating it is thought in Egypt or Chaldea, although China has very old astronomical records. In Egypt the study of astronomy was probably first stimulated by the phenomenon of the overflow of the Nile, upon which Egyptian civilization depended. The exact time of this phenomenon was a matter of importance and the passage of time was most easily marked by the movement of the stars. The first study of the heavenly bodies, made in order to mark the passage of time, soon led to a more detailed study for another purpose. It was noted that the Nile began to rise with the heliacal rising of Sirius. This coincidence was easily mistaken for cause and effect and if Sirius had such an extraordinary influence upon the affairs of men, the conclusion naturally followed that other stars must also have their influences. To ascertain the amount and character of these influences led to the study of astrology, which held man's attention for so long and enlarged considerably our knowledge of the heavenly bodies. In both Chaldea and China the desire to measure time accurately, as well as the wish to forecast the future, caused a careful study of the heavenly bodies. In Phœnicia the peculiar stimulus to the study of astronomy appears to have been the desire to obtain an accurate guide for traveling either by sea or land. The accurate marking of time, the requirements of travel and the desire to know the future were therefore the chief incentives for the study of astronomy, and the first two have been of continual service to society at all times.
The fact is worth noting that astronomy developed first in desert countries where the air is clear and the stars are easily visible the greater part of the time; in pastoral countries, too, where shepherds could follow