Mechanical calculator, Johann Jakob Sauter. Video curtesy of Gotesborg Stadsmuseum. IMPROVED AUDIO

Arithmometere. Charles Xavier Thomas, Colmar in Alsace, France, 1872.

How the Arithmometer Works, Charles Xavier Thomas, Colmar in Alsace, France, 1872

Gottfried Wilhelm Leibniz, 1672, demonstration video

Arithmometer calculator, Charles Xavier Thomas, Colmar in Alsace, France, 1872

Philipp Matthäus Hahn calculator 1770 1774, demonstration model

Astro-skeleton project. The summation conference call.

Robert Roskell, Liverpool, England, c.1840 skeleton clock

Watson orrery armature demo

Watson clockwork module finished

Watson 2nd wheel end shake repair

Watson technical overview 1

Watson demonstration overview

Theodor Kromer, A. G., Freiburg, Germany

Triple axis escapement model

Big Ben replica video

Oliver Pillard model #3, New Britain Bank Lock Co., 1875. Demonstration video.

New Britain Lock Co., Pillard model #3 movement, 1875

Dent epicyclical skeleton

Hall Premier double dial #3, c.1870 with Hall/Consolidated time lock, c.1882

Chicago Time lock/Diebold Marsh v 2, demonstration of bolt dog arming option.

Hollar Model 2, 1896. Initial powering up of the motor and solenoid systems

Hollar Model 2, 1896. Timer movement finished

Hollar Lock Inspection and Guarantee Co., Model 2, 1896, time lock demonstration video.

Consolidated Concussion and Calendar Time Lock

Yale Model 1

Demonstration of Yale Model #1 w. auto off-guard let off, c. 1876

Overmyer & Huston Model 1 time lock, 1876

Charles Fasoldt's entry in the 1876 Philadelphia Centennial Exposition winning a gold medal.

Tourbillon escapement model