Brass cased Tangent Galvanometer or Compass Galvo.
In good original condition and full working order, the coils test at 1006 ohms.
The silvered dial engraved SILVERTOWN LONDON is graduated in four 90 degree quadrants.
Made by The India Rubber, Gutta Percha and Telegraph Works Company.
Size:- 90mm diameter x 40mm deep, it weighs 604 grams.