English: Drawing of a precision astronomical regulator clock made by the E. Howard Clock Co., from a publication by Lick Observatory, CA, USA, 1887. The clock had a pendulum consisting of 4 containers of mercury that compensated for thermal expansion of the pendulum rod with temperature changes. It had a deadbeat escapement. It was installed at Lick Observatory and served to generate electric time signals that were distributed by telegraph wire to railroads and factories in the city of San Jose. For this it had internal switch contacts that generated signal every 2 seconds, connected to the 4 electrical terminal posts seen at the top of the clock. Alterations to image: cropped out second drawing showing clock with case open, and caption, which read: "The Howard mean-time clock".