An answer rather than a question (Why would a clock record time in Calcutta?)

[muuranker]

Just watching Antiques Roadshow, seeing a clock with dials showing the time in St. Petersburg, Calcutta and New York. It is marked 'Railway Time' - which dates it to after 1830, and before 1880 (the act of parliarment which replaces it with London time).

Now, we thought: _why_ would someone want to know what time it is in Calcutta (or St. Petersburg, or New York).

A quick debate over which came first - radio or cable telegraphy to North America - lead us to

http://www.atlantic-cable.com/Article/IAR/IndArchReviewArticle.htm
and
http://www.atlantic-cable.com/CableCos/India/index.htm

This narrows the dates considerably. There was a cable laid to Calcutta in 1859, but this failed, and another was laid in 1869.

So: dating this clock - I would say 1870s. Function: I would say the public hall of a telegraph office.

Isn't gutta percha a wonderful invention!