首页 / 官方藏书 / The American Electro Magnetic Telegraph / With the Reports of Congress, and a Description of All Telegraphs Known, Employing Electricity or Galvanism / Improvement in the Magneto Electric Machine, and Application of this Instrument to operate the Magnetic Telegraph.

Improvement in the Magneto Electric Machine, and Application of this Instrument to operate the Magnetic Telegraph.

The American Electro Magnetic Telegraph / With the Reports of Congress, and a Description of All Telegraphs Known, Employing Electricity or Galvanism · Alfred Vail · 第 7 / 16 章