Scientific American Supplement, No. 530, February 27, 1886Various
Science
Scientific American Supplement, No. 530, February 27, 1886
Various
Science -- Periodicals
Researches in faint nebulæ and nebulous stars appearing likely to
constitute a separate and interesting branch of the astronomy of the
future, it has seemed to me that the astronomers engaged in this work may
like to make a careful examination of some of the stars entered in my
observing book under the category of "suspected objects." The method I
adopted of insuring re-observation of these objects was by the
determination, not of their absolute, but only of their relative,
positions, through the agency of the larger "finder" of the great
telescope. This has an aperture of five inches, a power of thirty
diameters, and a field of view of seventy-eight minutes of arc. Two
diagrams were usually drawn in the book for each of these objects, the
one showing the relation of adjacent objects in the great telescope, and
the other the configuration of the more conspicuous objects in the field
of view of the finder. Adjacent to these "finder" diagrams are the
settings--to the nearest minute of arc in declination, and of time in
right ascension--as read from the large finding-circles, divided in black
and white. The field of view of the finder is crossed by two pairs of
hairlines, making a square of about twelve minutes on a side by their
intersection at the center. The diagrams in all cases represent the
objects as seen with an inverting eye-piece. As the adjustment of the
finder was occasionally verified, as well as the readings of the large
circles, there should be no trouble in identifying any of these objects,
notwithstanding the fact that no estimates of absolute magnitude were
recorded. The relative magnitudes, while intended to be only approximate,
are still shown with sufficient accuracy for the purpose of the research,
and the diagrams are, in general, faithful tracings from the original
memoranda.
[Mr. Todd transcribes the observing book entire.]
* * * * *
[AMERICAN ANNALS OF THE DEAF AND DUMB.]
NOTES ON MANUAL SPELLING.
The inestimable value of speech-reading and the practicability of its
acquisition under favorable conditions is a matter of common experience
and observation but justice to the deaf requires a recognition of the
fact that speech-reading has its limitations. Certain English words,
chiefly short ones, are practically alike to the speech-reader and the
context may fail sometimes to give a clew. It is necessary, at times, in
communicating with even expert speech-readers, to have recourse to
writing or oral spelling to convey the names of persons, places,
technical terms, etc., not in common use. Moreover, it is convenient to
have accurate and rapid means of conversation under unfavorable
conditions as to light and distance, or when from any cause the deaf
person's voice cannot be heard.
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