Front:
WENZEL PNEUMATIC MASTER CLOCK WITH SLAVE UNITS
R CLOCK
ANT ST SAN TRANCCE. PATINTED CT.277
Back:
Air Clock: in 1877 Herman J. Wenzel,
San Francisco, invented a master clock
to synchronize time in public buildings.
Electric master clocks replaced the Wen-
zel Air Clock and after the 1906 earth-
quake manufacture was stopped. The
only operating example is at Urban
Antiques at Seawall "B", 1861 Union,
San Francisco, California 94123.
Photo by David Weckler of Photo West-
sc13049
