Page:Popular Science Monthly Volume 22.djvu/845

Rh  of the State of New York might with equal propriety measure the value of the common-school system by the commercial value of their school-houses and grounds. The absurdity would be equally as great in the one as in the other case. Like the system of public education, the results of the Geological Survey have penetrated into every school district and into every corner of the State; and these results are not to be measured by the figures representing dollars, but by the increased intelligence of the people, and the proud satisfaction that we have been able to lay broad and deep the foundations of geological science in the soil of a people whose motto is "Excelsior."

 

HE significance of the astronomical portion of the calendar is materially different at present from what it was in the earlier stages of its development. That this may be clearly understood, and the modern problem with which astronomy has to deal in the yearly construction of the calendar justly appreciated, let us examine the history of its origin.

The word "calendar" is derived from calendium, denoting the commencements of months, which, in the language of ancient Rome, were called dies calendæ, or simply calendæ; i. e., clays on which "calling out" should occur, from "calo" I call. This "calling out" took place upon the reappearance of the small crescent after new moon, and at the present day remains the custom among those people who, as for instance the Turks, reckon time wholly from the recurring phases of the moon. This was loudly proclaimed from the roofs of public buildings by appointed priests or seers, who were required to seek for the moon's crescent in the evening sky either two days after new moon, or four or five days after the last appearance of its light in the morning sky; this, then, was established as the beginning of the month, the single days being reckoned by counting backward or forward from the night, or from the intermediate day of full moon. This method of reckoning time from the revolutions and phases of light of the moon has been long practiced in those countries in which the constant clearness of the heavens enables people to determine with considerable accuracy the first appearance of the moonlight, the so-called "new light," and, again, among those whose limited intercourse with other nations afforded no comparison of fixed standards. In 