Page:Philosophical Transactions - Volume 095.djvu/284

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Dr. Herschel on the Direction of the

a minimum, the line p a, when s p is given, will also be a minimum; and if all the m a's in Fig. 4 are minima, it follows also that all the s p's, whatever they may be, will give the p a's as small as possible: and this is the point that was to be established.

Whatever therefore may be the sum of real motions inquired to account for the phenomena of proper motions, our foregoing arguments cannot be affected by the result; for, as by observation it is known that proper motions do exist, and since no solar motion can resolve them intirely into parallactic ones, we ought to give the preference to that direction of the motion of the Sun which will take away more real motion than any other, and this, as we have shown, will be done when the right ascension of the apex is 245° 52' 30", and its north polar distance 40° 22'.