Longitude

[Joe Varo]

Just finished the book.  It's a short, quick, easy read which just give an
overview on the difficulties of determining longitude for sea navigation.
Apparently latitude was rather easy to determine, but not so with
longitude.  Also deals with the politics involved in a contest established
to invent the first reliable method of determining longitude.

By the way, can anyone tell me what the difference is between a "mile" and
a "nautical mile".  This is something I've always wondered about but have
never been able (or willing to look hard enough) to find a satisfactory
answer.  I know there's a conversion formula for miles to naut. miles, but
what is the purpose of the difference?

Is there a metric equivalent, like a "nautical kilometer" or something?

Joe