A Holosteric Barometer, bronze box, enamelled dial, original case, French, 19th C. (2nd half), signs of use, mechanism requiring maintenance, marked MAISON L ' ING[ENIEU]R CHEVALLIER, OPT[ICI]EN - PLACE DU PONT-NEUF 15, PARIS and M.O.P. Dimensões (altura x comprimento x largura) - 4 x 8,5 cm