Stetson line of position plotter
Date: circa 1928
Inventory Number: 2001-1-0024
Classification: Plotting device
Dimensions:31.8 × 39.4 × 3.5 cm (12 1/2 × 15 1/2 × 1 3/8 in.)
DescriptionAluminum plotting table with specialized plotting paper, one metal T-square, and one transparent celluloid panel.
The surface of the plotting table is etched with a diagonal grid. Visible through a slit near the left edge of the table is an aluminum cylinder printed with sixteen scales. The cylinder is rotated by turning a black knurled knob at the top edge of the plane table.
There are four metal clips along the top and bottom edges of the drafting table. Also visible along the top and bottom edges are metal bolts joining the surface and sides of the table.
Two metal plaques bolted to one side of the drafting table are printed with information on the plane table's manufacturer.
The plotting table opens to reveal a space for storage.
The crossbar on the T-square is painted black. There are two scales printed along its long bar. Along the top edge of the bar is a scale for "ARL," graduated into minutes. Along the bottom edge of the bar is a scale for "TIME", graduated into 2.5 minutes.
The yellowed celluloid panel is engraved with a rectangular grid.
The plotter is accompanied by several sheets of specialized plotting paper.
Signedprinted on bottom plaque bolted to side of table: MADE BY / EASTERN SCIENCE / SUPPLY COMPANY / BOSTON, MASS., U.S.A.;
printed on long bar of T-square, right center: Manufactured by Eastern Science Supply Company, Boston, Mass.
Inscribedprinted on top plaque bolted to side of table: PATENT APPLIED FOR;
printed on long bar T-square, left center: STETSON LINE OF POSITION PLOTTER
FunctionFor determining location at sea.
Primary SourcesSee this abstract in Popular Astronomy for H. T. Stetson's description of the instrument's use.