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Re: Table for Finding the Distance of Observed Terrestrial Objects at Sea
From: Paul Bedel
Date: 2022 Jun 10, 08:35 -0700
From: Paul Bedel
Date: 2022 Jun 10, 08:35 -0700
Hi, Robert,
In the french treatise of navigation "Traité complet de la navigation", by Jean BOUGUER, published in 1698, there is a table giving the dip and the distance of the horizon as function of the observator's eye above the sea water.
In this table, the elevation of eye is expressed in french feet (about 0,3248 meter) and the distance of the horizon in nautical leagues of 3 nautical miles. Dip is expressed in arc minutes.
Jean BOUGUER (1652-1714) was "Professeur royal d'hydrographie" in Le Croisic (near Saint-Nazaire). His son, Pierre BOUGUER (1698-1758) , was also "Professeur royal d'hydrographie" in Le Havre and Le Croisic; he was also astronomer, mathematician and physicist.
The book is digitized by Google.
Regards. Paul.
