An antique quackery hearing aid with two metal galvanic  ear pieces which fit around the pinnae.

The ear pieces are made from two plates, one tin which rests on skin, the other copper which has fleshed toned colouring (hence ‘Invisible’). The auditory benefits were attributed to magnetism and the box comes with its own ‘Galvanometer’ (which is actually a simple compass) and does confirm that they are magnetic. The case is marked in silver lettering ‘Audiphone Invisible Bernard  19 Rue de la Pepiniere Paris’.

You can read a French newspaper clipping from Feb 1901 extolling their virtues.

• From the Phisick collection