I had the opportunity to work with Roger at Mark Williams Company. One of his side-side projects was to work out a method of calculating the local time at any l

I had the opportunity to work with Roger at Mark Williams Company. One of his side-side projects was to work out a method of calculating the local time at any location in the US at any historical point. This turns out to be rather difficult, as, for example, Indiana at one point had a county-by-county choice as to whether or not they would do Daylight time, or Chicago time, or neither.