A rare and unusual early 20th Century Aviation Barograph, Jules Richard, 20 Rue Mellngue 25 Paris

A rare and unusual early 20th Century Aviation Barograph, Jules Richard, 20 Rue Mellngue 25 Paris, the hinged rectangular case with brass carry handle and clips to one end with a plinth base beneath a single glazed panel and bearing a paper label to the interior bearing increments and adjustment from 0 to 3000 metres, and corresponding decreasing barometric pressure, to a signed lacquered brass five bellow mechanism Numbered 82841, with a six hour duration brass drum with applied paper label, width 7”