THE

AMERICAN JOURNAL

OF

SCIENCE AND ARTS.

EDITORS AND PROPRIETORS,

PROFESSORS JAMES D. DANA AND B. SILLIMAN.

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. VII.-[WHOLE NUMBER, CVII.]

Nos. 37-42.

JANUARY TO JUNE, 1874.

WITH EIGHT PLATES.

NEW HAVEN: EDITORS.

1874.

PRINTED BY TUTTLE, MOREHOUSE & TAYLOR, 221 STATE ST.