5 down to below the ninth.
A chart of the relative displacements indicated for Bessel's stars by
the differences in their inter-mutual positions as determined at
Konigsberg and Yale accompanies the paper before us. Divergences
exceeding 0.40" (taken as the limit of probable error) are regarded as
due to real motion; and this is the case with twenty-six stars besides
the half dozen already mentioned as destined deserters from the group.
With these last may be associated two stars surmised, for an opposite
reason, to stand aloof from it. Instead of tarrying behind, they are
hurrying on in front.
An excess of the proper movement of their companions belongs to them;
and since that movement is presumably an effect of secular parallax,
we are justified in inferring their possession of an extra share of it
to signify their greater proximity to the sun. Hence, of all the stars
in the Pleiades these are the most likely to have a measurable annual
parallax. One is a star a little above the seventh magnitude,
distinguished as _s_ Pleiadum; the other, of about the eighth, is
numbered 25 in Bessel's list. Dr. Elkin has not omitted to remark that
the conjecture of their disconnection from the cluster is confirmed by
the circumstance that its typical spectrum (as shown on Prof.
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