Longitude

[Joe Varo]

Thanks to Murthy, Bruce and David for their clarifications of "nautical
miles".

So the reason for using nautical miles in air and sea travel is that by
these two modes of transportation you're more closely traveling along a
perfect sphere, whereas on land you have to deal with and traverse a more
irregular terrain?

Another question:  is the nautical mile part of the metric system?  Do
pilots from countries other than the US reckon their distances in
kilometers or nautical miles?  Is the kilometer, for some reason, equally 
accurate over both land and sea?

I realize that this has nothing to do with Pynchon...but who knows, it
might be useful for M&D.