Source: Stelzner Tauchertechnik:

Nach einer Mitteilung der Firma Siebe, Gorman –baute 1875 das aus Metall und Leder bestehende Gerat Bild 45 (page 41) Die Hande waren Frei, die Beine wurden anscheinend in der Langsrichtung gedruckt.

After 1872, experiments were made with a form of rigid metal diving dress or, more appropriately, diving armour. An early example, the design of wich followed, the shape of the human body, was produced in 1875 by a Frenchman named Lafayette. About three years later the French brothers Carmagnolle designed a complete suit of heavy armour incorporating mechanical joints, and actually produced one in 1882.

I was not able to find more information about Lafayette. He seems to be a north American but I could not find any evidence. I would be very pleased to receive additional information about Mr. Lafayette.