National Institute of Standards and Technology.
As the NIST website reads, "The Time and Frequency Division, part of NIST's Physics Laboratory, maintains the standard for frequency and time interval for the United States, provides official time to the United States, and carries out a broad program of research
and service activities in time and frequency metrology." Here is the direct link to the clock! http://nist.time.gov/timezone.cgi?Eastern/d/-5/java Sara Sara Schechner, Ph.D. David P. Wheatland Curator Collection of Historical Scientific Instruments Harvard University, Science Center B-6 Cambridge, MA 02138 Tel: 617-496-9542 Fax: 617-496-5932 -
