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Nersac: Un Poste Optique (Zoom) | by signal mirror
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Nersac: Un Poste Optique (Zoom)

This 1910s French Postcard is NOT my work, but I believe it in the public domain in the US as a work published prior to 1923.

 

This is a closeup zoom of the apparatus shown in my French postcard, postmarked 1905, showing French military telegraphists with the their visual telegraph, the "Mangin Apparatus", that served as a heliograph in sunlight, and a signal lamp at night or under clouds. I've also posted a cross-sectional diagram and the full front scan of the postcard.

 

A 1913 French article on this, and other types of French, English and American heliographs may be found here: gallica.bnf.fr/ark:/12148/bpt6k65514029/f351.image.r=lese...

 

I claim no copyright on this, you may use it as your laws allow. Attribution is not required, but a link back to this page would be appreciated.

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Taken on May 17, 2014