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mechanically, without the slightest need
for readjustment until 1 March 2100.
All these are interlinked by the ingenious
mechanism of a genuine, entirely mecha-
nical programme: merely changing the
initial date thus effects the appropriate
changes in all other functions.
Our time measurement is based on the
Gregorian calendar, i.e. a year of 365 days,
5 hours, 48 minutes, and 46 seconds, or
in decimals, 365.242192 days. In practice,
the yearly excess of just less than a quar-
ter (0.242192) of a day is corrected by
the 29th February in leap years. The few
missing decimals are then compensated
for every 100 years, by excluding 29th Fe-
bruary.
For the sake of greater precision, this ex-
clusion does not take place when the nu-
mber of centuries is divisible by 4. Such
is the case for the years 2000 and 2400
