I, however, have been bestirring myself to put amateurs upon a
more convenient and, I think, a better mode of examining double
stars than by the wire micrometer, with its faults of
illumination, fiddling, jumps, and dirty lamps. This is by the
beautiful method of rock-crystal prisms, not the Rochon method
of double-image, but by thin wedges cut to given angles. I have
told Mr. Alvan Clark my "experiences." and I hope he will apply
his excellent mind to the scheme. I am insisting upon this point
in some astronomical twaddle which I am now printing, and of
which I shall soon have to request your acceptance of a copy.
There is a very important department which calls for a zealous
amateur or two, namely, the colors of double stars, for these
have usually been noted after the eye has been fatigued with
observing in illuminated fields. The volume I hope to
forward--_en hommage_--will contain all the pros and cons of
this branch.
There is, for ultimate utility, nothing like forming a plan and
then steadily following it. Those who profess they will attend
to everything often fall short of the mark. The division of
labor leads to beneficial conclusions as well in astronomy as in
mechanics and arts.
Mrs. Smyth and my daughter unite with me in wishing you all
happiness and success; and believe me
My dear Miss Mitchell,
Yours very faithfully,
W.
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