Time of day "at any place in the world" calculator
From my collection.
|The central rotor is turned to align local time with the location printed around the outside. This has been set up for 6 pm in London at the bottom of the calculator. Times read off from the pink zone are a day ahead.
|The locations around the outer scale are (clockwise from London):
|Greenwich / London
|Madrid / Edinburgh
|Salt Lake City
|Batavia / Saigon
|Madras / Columbo
|Cyprus / Suez
|Cape Town / Stockholm
|These are as spelt at the time on the device and the fascinating thing is that each entry has a precise time reading - not to the nearest hour as we do now. (eg Madrid / Edinburgh are shown to be about 10 minutes behind London.)
|There is an indication on the appropriate hour lines of Eastern Standard Time; Central Standard Time; Mountain Standard Time and Pacific Standard Time (all USA) as well as Japanese Standard Time and Indian Standard Time. No standard times for are shown for Europe though. (Time zones in the USA were first proposed in 1884 but only became mandatory in 1918. It seems standard time for the whole country was brought in in the UK in 1880...)
|Text on the device states:
|Set the Hour Card for the time at a given place. The time at all other places will at once be indicated. Places against the red sector have the date ahead; places not on the red sector are the date before.