Chapter IX

, published in Appletons' Popular Science Monthly. The author, it is needless to say, was much gratified by the expressed wish of many readers that these scattered papers should be revised and collected in a more permanent form. As bearing upon the general subject of the book, a chapter has been added, at the end, treating on the question of the existence of planets among the stars. This also first appeared in the periodical above mentioned.

In conclusion, the author wishes for his readers as great a pleasure in the use of the telescope as he himself has enjoyed.

G. P. S.

BOROUGH OF BROOKLYN, NEW YORK, _January, 1901_.

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