[37] Long after Herschel had abandoned this idea, it continued current among astronomers. The successes of Lord Rosse's telescope perpetuated to the middle of the nineteenth century an erroneous view which Herschel had given up in 1791.

[38] These have never been re-observed. They should be sought for with a powerful refractor, taking special precautions against the illumination of the field of view from neighboring bright stars. Herschel's reflectors were specially open to illusions produced in this way. His observations probably will remain untested until some large telescope is used in the way he adopted, i. e., in sweeping.

BIBLIOGRAPHY.

I.—List of the Published Writings of William Herschel on Astronomical Subjects.

[In chronological order.]

N.B.—In general, translations and abstracts of those which appeared in periodicals are not noticed here. I have made exceptions in the more important cases.

[Solution of a prize question. See this book, [page 46].]

Ladies' Diary, 1779.