Felsenthal Graphical Firing Table

Description
This two-sided wooden instrument has a white coating and a plastic indicator with wooden edges held together by six brass rivets. The rule was designed by Felsenthal Instrument Company of Chicago. According to the accession file, this rule was made around 1960 at the Fort Sill Bookstore in Oklahoma. It is used to position a 155 mm howitzer armed with high-explosive M107 shells. One side is used for charges of 4, and the other side is used for charges of 5.
Both sides have scales for deflection correction or drift, the number of mils needed to move the explosion 100 meters, range, elevation, fuze setting, change in angle elevation needed to produce a change in range, and correction to fuze setting.
One side is marked: HOW 155mm (/) 155AH2H3M107 (/) CHARGE 4 (/) FSN 1220-937-8282. The other side is marked: HOW 155mm (/) 155AH2H3M107 (/) CHARGE 5 (/) FSN 1220-937-8282. Compare to 2005.2071.02 and to the graphical site tables, 1977.1141.26, and 1977.1141.27. Unlike this object, all three instruments have scales on slides.
References: U.S. Marine Corps, "Chapter 7: Firing Tables, Section II: Graphical Firing Tables," Tactics, Techniques, and Procedures for Field Artillery Manual Cannon Gunnery, Field Manual No. 6–40/MCWP 3–16.4 (Washington, D.C., 23 April 1996); Elizabeth R. Dickinson, "The Production of Firing Tables for Cannon Artillery," U.S. Army Ballistic Research Laboratory, Report No. 1371 (Aberdeen (Md.) Proving Ground, November 1967), 59–65, 75–80; accession file.
Location
Currently not on view
Object Name
scale rule
rule
date made
ca 1960
maker
Felsenthal Instrument Co.
Physical Description
wood (overall material)
metal (overall material)
plastic (overall material)
Measurements
overall: .9 cm x 45.6 cm x 11.1 cm; 11/32 in x 17 15/16 in x 4 3/8 in
place made
United States: Oklahoma, Fort Sill
ID Number
1977.1141.25
catalog number
336409
accession number
1977.1141
subject
Scale Rules
Science & Mathematics
Mathematics
Rule, Measuring
Artillery
See more items in
Medicine and Science: Mathematics
Scale Rules
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Ben Wharton Rau and Margery Felsenthal Rau

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