How to look up historical time zones by date and location

[Rustom Mody]

On Monday, August 18, 2014 7:21:53 PM UTC+5:30, Joel Goldstick wrote:
> On Mon, Aug 18, 2014 at 9:12 AM, luofeiyu  wrote:
> > I found that it is a concept LMT local mean time can express my meaning.

> Local Mean Time is time based on the actually astronomical position of
> the sun.  It is defined as 12 noon when the sun is at its high point,
> directly south in the sky.  This is the time you get when you read a
> sundial!
> So each town or village set their clocks differently.  That all
> changed with the railroad industry.  Once trains began traveling, time
> zones were invented so that everyone knew exactly what time it was in
> order to keep trains from meeting on the same tracks and colliding.
> Trains need time schedules.  Time zones make this possible.

Add to that the fact that any two places even say a kilometer apart,
will have different LMT.
Naturally if one chooses a least count, say 1 sec, then that distance will 
be larger.

40075 km equatorial circumference
86400 secs in a day (60×60×24)

40075/86400 = 2.1 

ie LMT changes by 1 sec for every 2.1 km E-W along the equator

And even here the distance would shrink going towards the poles.