Relvas's New Life Boat.--With engraving

Experiments with Double Barreled Guns and Rifles.
--Cause of the divergence of the charge.--4 figures

Improved Ball Turning Machine.--1 figure

Cooling Apparatus for Injection Water.--With engraving

Corrugated Disk Pulleys.--1 engraving

III. TECHNOLOGY.--A New Standard Light

Dr. Feussner's New Polarizing Prism.--Points of difference
between the old and new prisms.--By P.R. SLEEMAN

Density and Pressure of Detonating Gas

IV. ELECTRICITY, LIGHT, ETC.--Early History of the Telegraph.
--Pyrsia, or the system of telegraphy among the Greeks.
--Communication by means of characters and the telescope.
--Introduction of the magnetic telegraph between Baltimore
and Washington

The Kravogl Electro Motor and its Conversion Into a Dynamo
Electric Machine.--5 figures

Bornhardt's Electric Machine for Blasting in Mines.
--15 figures