A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ed Popko
Date: 2016 Jun 25, 02:48 -0700
I'm a great fan of Patrick O'Brian's Aubrey/Maturin 19th c British Naval series and I'm rereading the set (21) once again. Occasionally navigation methods are mentioned and I particularly laugh at this exchange between Captain Jack Aubrey and his ship's surgeon Stephen Maturin (who despite years sailing with Jack still knows little about what makes 19th c ships tick).
From "The Surgeon's Mate", book 7, pp. 276-278 by Patrick O'Brian, Norton press.
The setting - a mate has accidently dropped and broken the ship's chronometer. Captain Aubrey is asking to borrow Maturin's expensive personal Bregurt timepiece. Maturin does not understand why Aubrey would care about precise time and why losing the ship's chronometer is a calamity. Aubrey tries to explain the relationship of time, longitude and finding their way ...
SM 'The machine is used for finding out the latitude, I believe?'
JA 'To tell you the truth, Stephen, most people rely on the sextant for their latitude: the timekeeper is more for the other thing - east and west, you know.'
SM 'East and west of what, for all love?'
JA 'Why, of Greenwich, naturally.'
SM 'I am no great navigator - ' said Stephen.
JA 'You are too modest,' said Jack.
SM '- though I have often wondered how you mariners find your way about the dank wastes of ocean. But from what you tell me I see that for your countrymen Greenwich rather than Jerusalem is the navel of the universe - lo, Greenwich, where many a shrew is in, ha, ha - and secondly that whereas a poor man can fix his position only with regard to north and south, to up and down, his wealthy brother is secure to right and left as well. There is no doubt a logic in this, although it escapes me, just as the use of the timepiece escapes me, with it peevish insistence upon accuracy in the measurement of what is after all a most debatable concept, quite unknown, we are told, in Heaven. Tell me, is it really capable of telling you where you are, or is this just another of your naval - I must not say superstitions - like saluting the purely hypothetical crucifix on the quarterdeck?
JA 'If you have exact Greenwich time aboard - if you carry it with you - you can fix your longitude exactly by accurate observation of the local noon, to say nothing of occultations of the finer points. I have a pair of Arnolds at home - how I wish I had brought 'em - that only gained twenty seconds from Plymouth to Bermuda. In these waters that would tell you where you were, east of west, to within three miles or so. Oh, the lunarians may say what they please, but a well-tempered chronometer is the sweetest thing! Suppose you were riding along, with your watch set to Greenwich time in your pocket, and suppose you happened to take a noon observation and found that the sun southed at five minutes after twelve, you would know that you were almost exactly on the meridian of Winchester, without having to search for a finger-post. And the same applies to the sea, where finger-posts are tolerably uncommon.'
SM 'Heavens, Jack, what things you tell me. And I dare say this would answer for let us say Dublin and Galway?'
JA 'I should not care to affirm anything about Ireland, where people have the strangest notion of time; but at sea, I do assure you, it answers very well. That is why I should like to borrow your watch.'