The Evolution of the Quartz Crystal Clock* 



By WARREN A. HARRISON 



SOME of the earliest documents in human history relate to man's interest 

 in timekeeping. This interest arose partly because of his curiosity about 

 the visible world around him, and partly because the art of time measure- 

 ment became an increasingly important part of living as the need for cooper- 

 ation between the members of expanding groups increased. There are still in 

 existence devices believed to have been made by the Egyptians six thousand 

 years ago for the purpose of telling time from the stars, and there is good 

 reason to believe that they were in quite general use by the better educated 

 people of that period.^ Since that period there has been a continuous use 

 and improvement of timekeeping methods and devices, following sometimes 

 quite independent lines, but developing through a long series of new ideas 

 and refinements into the very precise means at our disposal today. 



The art of timekeeping and time measurement is of very great value, both 

 from its direct social use in permitting time tables and schedules to be made, 

 and in its relation to other arts and the sciences in which the measurement 

 of rate and duration assume ever increasing importance. The early history 

 of timekeeping was concerned almost entirely with the first of these and for 

 many centuries the chief purpose of timekeeping devices was to provide 

 means for the approximate subdivision of the day, particularly of the day- 

 light hours. 



The most obvious events marking the passage of time were the rising and 

 setting of the sun and its continuous apparent motion from east to west 

 through the sky. The first practical measure of the position of the sun of 

 which any record is known was the position or the length of shadows of 

 fixed objects, resulting through a long period of development in the well- 

 known sundial in its many forms. But the sundial was in no sense an 

 instrument of precision and in no sense could be considered as a time keeping 

 device. Even after the development which resulted in mounting the 

 gnomon parallel with the axis of the earth, the largest, most elaborate, and 

 most carefully made instruments could at best indicate local solar time. 

 Furthermore, the sundial has value only in daylight hours and then only on 



* The subject matter of this paper was given before the British Horological Institute in 

 London on the occasion of the presentation of the Horological Institute's Gold Metal for 

 1947 to Mr. Marrison in consideration of his contribution toward the development of the 

 quartz crystal clock. The present text is substantially as published in the Horological 

 Journal. 



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