WWI navigational aid, variable speed
Date1923
Inventory Number2007-1-0119a
ClassificationNavigational Instrument
Subject
Maker
American
?
Cultural Region
Dimensions29.2 × 26.9 × 0.2 cm (11 1/2 × 10 9/16 × 1/16 in.)
Material
DescriptionA flat sheet of yellow clear celluloid (?) with black printed markings. One edge of the sheet is a semi-circular arc. There is a rotating arm attached to the center of the semi-circle with a metal divot. The arm is labeled "SPEED RATIO SCALE". The arm has a black line down the center, and a scale from 1.0 to 2.5 along that line in 0.5 increments. It is covered with a piece of paper with handwritten "yard" measurements on it.
The curved edge of the sheet has degree markings on it from 5° to 170°. Each degree marking is written twice such that the scale can be read from either side of the clear plastic sheet. Each set of degree markings accompanies a black line. At the 170° end of the circle, the lines are straight but the lines become increasingly curved as they approach the 5° end. The lines are labeled "CURVED LINES REPRESENT COURSE ANGLE".
Seven vertical lines run parallel to the straight edge of the sheet. Every other line is bold with an upward pointing arrow at one end. These lines are labeled "COURSE OF GUIDE".
The curved edge of the sheet has degree markings on it from 5° to 170°. Each degree marking is written twice such that the scale can be read from either side of the clear plastic sheet. Each set of degree markings accompanies a black line. At the 170° end of the circle, the lines are straight but the lines become increasingly curved as they approach the 5° end. The lines are labeled "CURVED LINES REPRESENT COURSE ANGLE".
Seven vertical lines run parallel to the straight edge of the sheet. Every other line is bold with an upward pointing arrow at one end. These lines are labeled "COURSE OF GUIDE".
Signedhandwritten in black in bottom corner of instrument: R.W. / 5-10-23
Inscribedprinted in black on plastic sheet: ANY SPEED / COURSE ANGLE CARD / MARK I
Curatorial RemarksThese three items (2007-1-0119a,b,c) were found during photo inventory in a manila envelope labeled "WWI - navigational aids" on shelf A17-E1 alongside 1997-1-1868 (Webster Astro-computograph). Apparently associated with that item because they were acquired around the same time (mid-1970s) from the same donor.
It is described as WWI (1914-1918) but at the same time appears to be dated 1923.
FunctionThis is a navigational instrument for determining course angles at variable speeds. Object was designed for use in WWI.
ProvenancePrivate donor to the Collection, 1977.
Jakob Amsler
Date: circa 1906
Accessories: instrument is in four (4) parts; the rail is in own box and is inventory # 2006-1-0002b; letter from Prof. William Brower containing the complete history of ownership and use (missing)
Object number: 2006-1-0002a
Damon Engineering, Inc.
Date: 1962-1972
Accessories: white folded paper listing contents and instructions
Object number: 2006-1-0098
Walter Balcke
Date: 1952-1964
Accessories: mahogany box; cardboard instruction card
Object number: 1997-1-1601
Gebrüder Haff
Date: 1960-1969
Accessories: plush-lined, hard green case
white card with instrument information in case
Object number: 1999-1-0005
William Cary
Date: 1790-1820
Accessories: original mahogany box (lid warped with cracks in two places)
Object number: DW0281
Walter Balcke
Date: 1952-1964
Accessories: mahogany case; two circular protractors; clear plexiglass rule with serated edge
Object number: 1990-5-0028
Charles W. Dixey
Date: circa 1830
Accessories: silver framed green shagreen case
original curatorial cards and photos
Object number: DW0288
