A 19th century silver avitreous thermometer, identical to the better known Immisch model but by Maw, a 19th century medical instrument maker and retailer. It comes it it's original hemp lined hinged metal case. This is an unusual variation which I have not seen before. The build quality is to the same high standard as the Immisch although the dial is rather more ornate. It is signed MAW and below this London 6446 Patent. A rare medical thermometer designed to be held in the hand; in perfect working order.