A New Method of Keeping Mechanical Drawings. 4978

Achard's Electric Brake for Railway Use. 2 figures. Plan and

elevation. 4974

II. ELECTRICITY, ETC.--Electricity. What it is and what may be

expected of it. By JACOB REESE. 4974

Electric Light Apparatus for Photographic Purposes. By A.J.

JARMAN. 2 figures. 4976

Scientific American Supplement, No. 312, December 24, 1881 · 第 7 / 76 题