gunner's caliper with sector
Date: circa 1766
Inventory Number: DW0955
Classification: Gunner's caliper
Dimensions:sector open: 45.6 cm (17 15/16 in.)
closed: 0.2 x 26 x 5.8 cm (1/16 x 10 1/4 x 2 5/16 in.)
box: 4.4 × 31.4 × 28.9 cm (1 3/4 × 12 3/8 × 11 3/8 in.)
Accessories: original case
DescriptionThe brass arms are joined in a way that overlapping circular plates have readable scales at the hinge. Sector scales are inscribed on the arms. Steel points are set in the caliper tips.
Side A
sector scales:
line of lines ("Lin"), also known as line of equal parts
line of solids ("Sol")
line of planes ("Pla")
line of polygons ("Pol")
line of artificial tangents ("Tan.")
line of artificial sines ("Sines")
line of artificial versed sines ("Ver. Sines")
Gunter's line of numbers ("Num.")
hinge scales:
Iron
Brass
Guns
tables near caliper points:
conversion between English and French units (feet, lbs)
conversion between cubic inches and bushels
conversion between Troy and Avoirdupois weights (lbs, oz)
Side B
hinge scales:
"Shot Diameters"
"Bores of Guns"
"Pounders"
protractor with 3 scales 0°-180° running in both directions
tabulated mathematical relationships along the arms:
"Wt in lb Avoird. of a Cube Foot or Inch" of various materials including gold, mercury, lead, silver, copper, brass, steel, iron, tin, marble, stone, glass, brick, clay, sand, sea water, rain water, wine, brandy, oil, wheat, assorted woods, and brimstone.
"Rules for Shooting"
how "To raise Water"
"Fall of Bodies"
"No. of Shot or Shells in a Pile"
relationships between plane and solid figures
With original wooden case lined in scrap paper (printed on glued down side) and covered with sharkskin. Brass hinges and latch hooks. The hinges are separated.