The concepts and theories of modern physics / By J.B. Stallo.

  • John Stallo
Date:
1900
Catalogue details

Licence: In copyright

Credit: The concepts and theories of modern physics / By J.B. Stallo. Source: Wellcome Collection.

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    for them by the facts and natural laws of which they had knowledge. In the early part of the last century, Bradley (with the aid of Molyneux) made a series of telescopic observations of the star 7 Braconis, to the end of determining the amount of its ap])arent displace- ment due to the orbital motion of the earth, so as to detect the annual parallax of the fixed stars—an achieve- ment very desirable in Bradley’s time by reason of a standing objection to the Copernican system urged on the ground of the alleged absence of such a parallax. To his sui*prise he found a displacement different in direction and far greater in degree than that looked for. This anomaly had to be explained; and Bradley knew of no physical cause to which it could be assigned. He thouglit for a time of nutation ; then of refraction ; but he soon became satisfied that no explanation was af- forded by either fact. He was finally led, by a careful study of tlie variations in the direction and rate of the displacement, to look for a solution of the mystery in the composition between the velocity of light and that of the earth’s orbital motion, and thus became the dis- coverer of what is now known as the aberration of light. Amid all his perplexities, however, it does not appear at any time to have occurred to him that the anomalous jdienomenon could be the result of a constitutional c*rook in space. xVnd it may be asserted with confi- dence that there is no astronomer living to-day who would attribute the anomalous parallax, whose dis- covery I have supposed, to a spatial pseudo sphericity. For, irrespective of all other considerations, the astrono- mer would at once meet every suggestion of this sort with the objection that an inherent curvature of space ]u-esuppo8cs differences between its several parts—hete- rogeneities in its internal constitution — and that the