Chapter IV: ELECTRICITY, HEAT, ETC.--Gerard's Alternating Current

Machine.--2 engravings.

Automatic Fast Speed Telegraphy.--By THEO. F. TAYLOR.--Speed
determined by resistance and static capacity.--Experiments
Taylor's system.--With diagram.

Theory of the Action of the Carbon Microphone.--What is it?
--2 figures.

The Dembinski Telephone Transmitter.--3 figures.

New Gas Lighters.--Electric lighters.--3 engravings.

Distribution of Heat which is developed by Forging.