AMERICAN JOURNAL

OF

SCIENCE AND ARTS.

EDITORS AND PROPRIETORS,

JAMES D. DANA, B. SILLIMAN, AND E. S. DANA.

ASSOCIATE EDITORS,

PROFESSORS ASA GRAY AND WOLCOTT GIBBS,
OF CAMBRIDGE,

PROFESSORS H. A. NEWTON, S. W. JOHNSON,
GEO. J. BRUSH AND A. E. VERRILL,
OF NEW HAVEN,

PROFESSOR EDWARD C. PICKERING, OF Boston.

THIRD SERIES.

VOL. IX.-[WHOLE NUMBER, CIX.]

Nos. 49-54.

JANUARY TO JUNE, 1875.

WITH SEVEN PLATES.

NEW HAVEN: EDITORS.

1875.