General Information

Serial #

N/A

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

ALL BRASS CONSTRUCTION

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

15.2 cm

Width

15.2 cm

Height

1.7 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Exploration and Survey

Category

Measurement-position

Sub-Category

N/A

Manufacturer

AKA

Unknown

Country

Unknown

State/Province

Unknown

City

Unknown

Context

Country

Worldwide

State/Province

Unknown

Period

THIS TYPE OF INSTRUMENT USED IN 17TH-18TH CENTURIES

Canada

Unknown

Function

TO DETERMINE TIME, AND DETERMINE ALTITUDE. IF MOUNTED ABOVE A MAGNETIC COMPASS, IT CAN BE USED TO MEASURE MAGNETIC DECLINATION.

Technical

INVENTION ATTRIBUTED TO WILLIAM OUGHTRED (1575-1660) IN EARLY 17TH C., IT HAS ITS ROOTS IN ASTRONOMY, NAVIGATION & SURVEYING. AS WELL AS TELLING THE TIME, THIS DIAL WILL MEASURE MAGNETIC VARIATION (WHEN MOUNTED ABOVE A COMPASS), OR CAN BE USED AS AN ALTERNATIVE TO MARINER'S ASTROLABE FOR MEASURING SOLAR ALTITUDE AT NOON TO DISCOVER THE LATITUDE. (REF.1)

Area Notes

Unknown

Details

Markings

MERIDIAN RING (OUTER RING) GRADUATED 90-0-80 AT 10-MINUTE INTERVALS ON ONE SIDE; 0-90 AT 10-MINUTE INTERVALS ON REVERSE. INNER RING (ROMAN CHAPTER RING?) GRADUATED I-XII I-XII AT 5-MINUTE INTERVALS ON ONE SIDE & ON INNER EDGE OF CIRCLE/ PIVOTED BRIDGE FOR PINHOLE SIGHT GRADUATED WITH CALENDAR SCALE 'D N O S A J J/ D J F M A N J' - ON ONE SIDE; SIGNS OF THE ZODIAC & SCALE '20-10-AE-10-20' [SCALE FOR SUN'S MERIDIAN ALTITUDE?] INCISED ON REVERSE

Missing

1 SUPPORTING FITTING FOR INNER RING IS BROKEN BUT PRESENT. SUSPENSION RING & PINMISSING

Finish

Unknown

Decoration

N/A