Chapter IV: PHYSICS. ELECTRICITY, ETC.--Thury's Dynamo Electric Machine

--5 figures.

Breguet's Telephone.

Munro's Telephonic Experiments.--9 figures.

Apparatus for Maneuvering Bichromate of Potassa Piles from a
Distance.--2 figures.

Magnetic Rotations.--By E.L. VOICE.--1 figure.

Lighton's Immersion Illuminator.--1 figure.

Foucault's Pendulum Experiments.--By RICHARD A. PROCTOR.
--4 figures.