parallax. The parallax of the stars--and the consequent knowledge of
their distance--is obtained by observing them from opposite points
of the earth's orbit around the sun. When a star is within measurable
distance, these angles are acute, and the lines from the star to the
earth at opposite sides of its orbit converge, therefore. But when
these lines, as sometimes happens, appear to be _divergent_, the
result is called a _negative_ parallax, and is explainable by higher
space relationships. Obviously, the divergence of the lines would
indicate that the object lies _behind_ the observer instead of in
front of him. This anomaly can be explained by the curvature of space
in the fourth dimension. If space is so curved, the path of light
itself is curved also, and a man--were his vision immeasurably keen,
not to say telescopic--could see the back of his own head! It is not
worth while to give this question of negative parallax too much
importance, by reason of the probability of error, but in this
connection it should be stated that there appears to be an undue
number of negative parallaxes recorded.


GRAVITATION

Gravitation remains a puzzle to science. The tendency of modern
physics is to explain all material phenomena in terms of electrons
and the ether, but the attempt to account for gravitation in this
way is attended with difficulties. In order to cope with these, it
seems necessary to assume that our universe is only a portion of a
greater universe. This assumption readily lends itself to the
conception of our universe as a three-dimensional meeting place of
two portions of a universe of four dimensions--that is, its
conception as a "higher" surface. This is a fundamental postulate of