Tag Archives: Wilhelm Bröcking

The Boston Time-Ball

“I have intrusted Mr. Winslow Upton with the work of compiling the accompanying circular of information relative to time-balls, and have the honor to present herewith the results of his labor.”

– Cleveland Abbe, “Information Relative to the Construction and Maintenance of Time-Balls.” October 1881.

Winslow Upton was a “computer” (in the sense of one who computes) at the U.S. Naval Observatory in 1880. The following year he went to the U.S. Signal Service where he was tasked with compiling a summary on the practice of using time-balls for the distribution of accurate time.

Boston Time-Ball
The Boston Time-Ball in the dropped position with the hoisting and releasing machines to the right.

The practice of dropping a ball at exactly noon every day was used to calibrate the chronometers on ships in a nearby harbor. These accurate timepieces were then used for celestial navigation. The balls were installed on tall buildings within a couple of miles of the docked ships. An example is the Boston Time-Ball. The procedure used in Boston was described by B.M. Purssell of the Signal Corps in Upton’s compilation. Continue reading The Boston Time-Ball