Chapter · England · Land
No two simultaneous days
How Greenwich became the middle of the map
Before 1884 every meridian had its own day. This path reads the minutes of the conference that chose where to put the zero of longitude, and the reasons given there.
Context first
A lesson to read before the others, to set the scene.
- The place
- The era
- The people
No two simultaneous daysBefore 1884 every meridian had its own day and no two days on earth were simultaneous. Twenty-five nations met in Washington to choose where to put the zero.9 min
The lessons in this chapter
- 1Cutting no great continentFrance asks for a meridian of absolute neutrality that cuts no continent. The reply does not attack the principle: it requires a first-order observatory, and only four remain.10 min
- 2Seventy per cent of the shippingGreenwich was chosen not for its precision but for its installed base: more than seventy per cent of the world's shipping and three quarters of its chart plates.10 min
- 3Twenty-two votes to oneGreenwich is adopted by twenty-two votes to one with two abstentions. The resolutions that follow pass on fourteen votes, then fifteen, with continental Europe largely abstaining.10 min
How these lessons are written
Each lesson starts from first-hand sources: Wikisource, Gallica, Persée, archives, museums and institutes. A fact without a source does not get written, and every lesson lists its own as direct links.
The rhythm
A lesson is five minutes of cards and four questions. Those questions then come back the next day, then at 3, 7, 21 and 60 days, and that return is what makes it stick. One a day is enough, and you can do several in a row.