Page:Popular Science Monthly Volume 13.djvu/11

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THE

POPULAR SCIENCE

MONTHLY.



MAY, 1878.



THE RADIOMETER: A FRESH EVIDENCE OF A MOLECULAR UNIVERSE.[1]
By JOSIAH P. COOKE, Jr.
ERVING PROFESSOR OF CHEMISTRY AND MINERALOGY IN HARVARD UNIVERSITY.

NO one who is not familiar with the history of physical science can appreciate how very modern are those grand conceptions which add so much to the loftiness of scientific studies; and of the many who, on one of our starlit nights, look up into the depths of space, and are awed by the thoughts of that immensity which come crowding upon the mind, there are few, I imagine, who realize the fact that almost all the knowledge, which gives such great sublimity to that sight, is the result of comparatively recent scientific investigation; and that the most elementary student can now gain conceptions of the immensity of the universe of which the fathers of astronomy never dreamed. And how very grand are the familiar astronomical facts which the sight of the starry heavens suggests!

Those brilliant points are all suns like the one which forms the centre of our system, and around which our earth revolves; yet so inconceivably remote, that although moving through space with an incredible velocity they have not materially changed their relative position since recorded observations began. Compared with their distance, the distance of our own sun—92,000,000—miles seems as nothing; yet how inconceivable even that distance is when we endeavor to mete it out with our terrestrial standards! For, if, when Copernicus—the great father of modern astronomy—died, in 1543, just at the close of the Protestant Reformation, a messenger had started for the sun, and traveled ever since with the velocity of a railroad-train—thirty miles an hour—he would not yet have reached his destination!

  1. A lecture delivered in the Sanders Theatre of Harvard University, March 6, 1878.