# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: G F Martelli versus G Pouvreau
From: Frank Reed
Date: 2016 Mar 12, 11:55 -0800

Paul Bedel, you wrote: "there are no more Martelli's Mysteries as Cotter said"

Assuming that this is correct of Pouvreau's tables, then the explanation for the failure of Pouvreau's work is just as simple as that statement itself. He took away the mystery.

Navigation tables are today, and were historically, partly produced by government bureaucracies and partly produced by commercial operations. The rules for success are quite different. Martelli's tables were successful in the market precisely because navigators fell for his magic trick -- the idea that he had created some mathematically novel method for solving the same old problem. Navigators bought these tables, not because they understood them, but because they did not understand them. Magic works in the marketplace. Pouvreau perhaps made the mistake of lifting the curtain, revealing the simple tricks behind Martelli's sleight of hand. And nobody likes a spoilsport!

I'll add that this magic was not the only reason that specialized time sight tables could succeed. For the vast majority of nineteenth century and "Old School" twentieth century navigators, celestial navigation consisted of almost nothing but latitude by Noon Sun and longitude by time sight. There was one exceedingly common, nearly ubiquitous, technique for solving the time sight problem, which used the ordinary logarithms of trigonometric functions found in any manual of navigation (and that's what I teach in my Celestial Navigation 19th Century Methods class, which is being offered again next weekend at Mystic Seaport in Mystic, Connecticut USA). But for a navigator who never does any other kind of calculation, and also never aspires to anything more than basic celestial, those general tables could be counted as un-necessary baggage. For such minimalist navigators, specialized tables like Martelli's were a good option. In fact, it occurs to me that the sort of navigator who has no aspirations for anything more than the minimal calculations would also be the sort of personality who would find intrigue in the concept of a magical solution to a familiar old problem.

Here's an index of various earlier discussions of Martelli's tables. Lots of good reading in there. I point you to these, not to say that we shouldn't discuss these matters afresh now or to suggest that 'it's all in the acrhives', but so that you have access to as much background as you might wish.

Frank Reed
Conanicut Island USA

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