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