Description
This 1069 vintage ad for Planning Research Corporation has a color photograph of a woodcarving by William Ransom of Su Sung (1020-1101).
Year Published: 1969
Approximate overall size – inches: 9 x 12
Grade: Excellent
Excerpt:
“[Su Sung’s astronomical clock escapement] differs from the types of escapement of the later West because the action of the arrest is brought about not by any mechanical oscillation but by gravity exerted periodically as a continuous steady flow of liquid fills containers of limited size. The peculiar interest of the water-wheel link work escapement, hitherto unknown to historians of technology either in East or West, lies in the fact that it constitutes an intermediate stage or ‘missing link’ between time-measuring properties of liquid flow and those of mechanical oscillation. It thus unites, under the significant aegis of the millwright’s art, the clepsydra and the mechanical clock in one continuous line of evolution.”
This is a 54 yr. old original vintage ad removed from a 1969 publication and is not a reproduction of any kind.
