Description

HENRY SUTTON’S FORM OF MAGNETIC AZIMUTH DIALLING COMPASS, English, c. third quarter 17th century, unsigned. Set in an eight-sided wood mount, 4-3/4″ (12 cm) across, the compass has a fine printed card, a most elegantly shaped needle, and a circumferential wooden degree circle. The card has degree scales, twice-12 hour scales, calendar scale, solar declination scale, and 32-point rose. Condition is good noting the wood housing is cut on one side (where it may have attached to a plane table), the glass replaced. A similar dial face is shown on Henry Sutton’s 1654 trade card (see Derek Price in Singer et al., 1957), along with instructions to direct the south side of the compass card toward the sun, and read the time where the north end of the compass needle (in summer; south end in winter) crosses the hour lines along the proper parallel of solar declination (as read from the central circular table). A very rare dialling compass. The Museum of the History of Science in Oxford holds a boxwood diptych sundial mounted with a similar compass card, and owns a variant slightly earlier unmounted card signed “Henry Sutton Londini fecit *1653.*” The card design has been discussed in detail by Jim Bennett (Sphaera issue 10).