"Horizontal Pocket Sundial, Butterfield Paris, 17th Century"
Horizontal pocket sundial. Octagonal brass plate with indexes engraved with Roman and Arabic numerals. Dial called "a l'oiseau" adjustable according to the latitude. It is signed by the manufacturer Butterfield, who is the inventor of this type of dial. The latitude of 16 European cities is specified under the plate plus 5 under the compass bowl. Length 2,99 inches, width 2,63 inches. Late 17th or early 18th century. 
Le Magazine
Rivista Artiquariato
TRÉSORS magazine