Page:Popular Science Monthly Volume 16.djvu/11

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THE

 

POPULAR SCIENCE

 

MONTHLY.



NOVEMBER, 1879.



THE RECENT PROGRESS OF SOLAR PHYSICS[1]
By Professor S. P. LANGLEY,
OF THE ALLEGHENY OBSERVATORY

LEAVING to those of wider knowledge the survey of the whole field of scientific labor, it has seemed to me that I could best present to you some account of that branch of it with which I am most familiar, which is that of "Solar Physics."

This study is essentially a modern one. Astronomy, which in the earliest times could only mark the annual path of the sun, or count the stars, with the invention of the telescope still concerned itself more with the motions of the heavenly bodies than with their physical nature. It sought out new methods of precision to fix the places of these stars and to mark out for the navigator the path of the moon on the celestial dial; it united itself intimately with the sister science of mathematics in predicting the places of the heavenly bodies from the law of gravitation, but it was still as a surveyor and marker of boundaries in the field of space that the observer chiefly labored, and we associate the most striking triumphs of the classic astronomy with this work of precision. It is this aspect that appeals even to the imagination, and which is seized as distinctive by the poet of Urania:

"That little Vernier on whose slender lines

The midnight taper trembles as it shines,
Tells through the mist where dazzled Mercury burns,
And marks the spot where Uranus returns."

These are noble aims, and noble results; but it is curious to see how observers of the last century, who had learned this excellent lesson

  1. Address before the Physical Section of the American Scientific Association at Saratoga.