Historical German patents & torsion pendulum clocks. part I, DRPS 1877-1945 / D.K. Stevenson.

Stevenson, Douglas K.,

Historical German patents & torsion pendulum clocks. part I, DRPS 1877-1945 / D.K. Stevenson. Historical German patents and torsion pendulum clocks. part I, DRPS 1877-1945 - 138 pages ; 30 cm


Clocks and watches--Patents--Germany--19th century.
Clocks and watches--Patents--Germany--20th century.
Torsion pendulum.

Clock (general) patent torsion Stevenson, Douglas K. Ruhrei