NavList:

Noell Wilson, you wrote:
"Minutes on the arc are often divided into thirds and fourths"

Good point. And I know just what you mean. The main scale on the sextant arc is often divided into portions that are a third or a quarter of a degree. But, oh boy, calling those "thirds" and "fourths" gets you right into the linguistic hell of the Babylonian sexagesimal system! You could find this in Bowditch still (e.g.) in the early nineteenth century: a third was not a third of a degree... instead it was a sixtieth part of a second. There are 60' in 1°... there are 60" in one 1'... and there are 60''' in 1".

In another post you asked jokingly how this might come up in conversation. Try this on for size at your next "cocktail party"... If someone brings up time-keeping and the amazing synchronization of two smartphones, ask, "Hey did you ever wonder why seconds [of time] are called seconds? Did they lose a race or something??" Then you can get into "thirds" and 3000-year-old Babylisms and all that craziness. :)

Frank Reed