not
accurate enough to warrant so definite an inference. The Albany proper
motions, as Prof. Boss was careful to explain, depend for the most
part upon the right ascensions of Bessel's and Lalande's zones, and
are hence subject to large errors. Their study must be regarded as
suggestive rather than decisive.

A better quality and a larger quantity of material was disposed of by
the latest and perhaps the most laborious investigator of this
intricate problem. M. Oscar Stumpe, of Bonn (_Astr. Nach._, Nos.
2,999, 3,000), took his stars, to the number of 1,054, from various
quarters, if chiefly from Auwers' and Argelander's lists, critically
testing, however, the movement attributed to each of not less than 16"
a century. This he fixed as the limit of secure determination, unless
for stars observed with exceptional constancy and care. His discussion
of them is instructive in more ways than one. Adopting, the additional
computative burden imposed by it notwithstanding, Schonfeld's
modification of Airy's formulae, he introduced into his equations a
fifth unknown quantity expressive of a possible stellar drift in
galactic longitude. A negative result was obtained. No symptom came to
light of "rotation" in the plane of the Milky Way.

M. Stumpe's intrepid industry was further shown in disregard of
customary "scamping" subterfuges. Expedients for abbreviation vainly
spread their allurements; every one of his 2,108 equations was
separately and resolutely solved. A more important innovation was his
substitution of proper motion for magnitude as a criterion of
remoteness. Dividing his stars on this principle into four groups, he
obtained an apex for the sun's translation corresponding to each as
follows:

Number of Proper motion. Apex.
Group included stars. " " deg. deg.
I. 551 0.16 to 0.32 R.A. 287.4 Decl. +42.
II. 340 0.32 to 0.64 " 279.7 " 40.5
III. 105 0.64 to 1.28 " 287.9 " 32.1
IV. 58 1.28 and upward " 285.2 " 30.4

Here again we find a marked and progressive descent of the apex toward
the equator with the increasing swiftness of the objects serving for
its determination, leading to the suspicion that the most northerly
may be the most genuine position, because the one least affected by
stellar individualities of movement.

By n