Eight (8) Keuffel & Esser linear slide rulers, including two (2) made specially for the U.S. Military. 1st item: 4110 Power Trig, specifically produced for the U.S. Naval Academy. Comprised of a mahogany Mannheim Style frame, one side coated with white celluloid, plastic cursor with metal frame and white celluloid edges held together with metal screws. Maker's marks, front. Includes a brown leather case with gilt lettering reading "K&E SLIDE RULE 4110". Slide rule – 14 5/8" L. Case – 15 1/8" H x 2 1/2" W x 1 1/8" D. 2nd item: Short Base Triangulation, specifically produced for the U.S. Army. Comprised of one-sided off white laminate light colored hardwood and mahogany, plastic cursor with metal frame and white celluloid edges held together with metal screws. Maker's marks, front. Includes an orange leather case with gilt lettering reading "U.S." Slide rule – 21 3/4" L. Case – 22 1/4" H x 2 3/4" W x 1 1/4" D. 3rd item: 4082-3 Radio Special, serial number 769864. Comprised of two-sided white celluloid coated mahogany, frameless plastic cursor with plastic edges held together with metal screws, and L-shaped metal end pieces. Maker's marks, front and back. Includes an orange leather case. Slide rule – 12 1/2" L. Case – 13" H x 2 5/8" W x 7/8" D. 4th item: 4081-3 Log Log Decitrig Duplex, serial number 155803. Comprised of two-sided white celluloid coated mahogany, plastic indicator with metal frame and plastic edges held together with metal screws, and L-shaped metal end pieces. Maker's marks, front and back. Includes a black leather case with embossed lettering and metal loop. Slide rule – 12 1/2" L. Case – 13 1/8" H x 2 1/2" W x 1 1/4" D. 5th-6th items: Two (2) 4053-5 slide rules, no serial numbers. Comprised of mahogany Mannheim Style frames, one side and top and bottom edges coated with white celluloid laminate, each with a laminated paper label to back, glass frameless cursors with white celluloid edges held together with metal screws. Maker's marks, front. Includes two (2) black "Polyphase" boxes with gilt blindstamp lettering. Slide rules – 20 5/8" L. Boxes – 21" H x 2" H x 1" D. All items second quarter/mid 20th century. 7th-8th items: Two (2) unidentified slide rules, serial numbers 044201 and 799620. Comprised of mahogany Mannheim Style frames, one side and top and bottom edges coated with white laminate, laminated paper labels to back, plastic cursors with metal frames and white celluloid edges held together with metal screws. Maker's marks, front. Includes two (2) black leather cases, one (1) with gilt lettering reading "K&E SLIDE RULE" and a black leather case. Slide rule – 20 5/8" L. Cases – 21" H x 2 1/8" W x 1 1/4" D. Note: One theory is that this type of slide ruler were intended to be sold at college bookstores. (see: http://mccoys-kecatalogs.com/KEcollection/Mystery/kemysteryfamilyrules.htm). All items second quarter/mid 20th century. Provenance: Private West Tennessee Collection. CONDITION: 1st item: Wear, areas of black tape repair to case. 2nd item: USBR inscribed to edge of ruler and case. Wear to case. 3rd item: Wear, old stickers, area of repair, and ink inscription from previous owner to case. 4th-5th items: Wear to cases.