Collection of Four Vintage Slide Rules

A set of four vintage slide rules spanning American and Japanese makers, appealing to collectors, engineers, or anyone with an appreciation for pre-calculator computation tools.

The four rules:
- Keuffel & Esser (K&E) 10-inch - An early American-made rule, ivory-colored with brass end brackets and glass cursor. Marked "Pat. June 5, '00 Dec. 22, '03" and "Keuffel & Esser Co. N.Y.,
Made in U.S.A." Scales include D, F, B, S, T, C, I, D. Comes without a case.

- Frederick Post Co. No. 1447 - A bamboo-core rule made by Sun Hemmi in Japan for the American Post brand, in its original red cardboard box. The back of the box has handwritten engineering formulas. Scales include A, B, CI, C, D, K.

- Sun Hemmi (Post branded) long rule - A longer bamboo rule, also in a red cardboard box with handwritten notes. Comes with a tan leather belt case. Scales visible include LL, DF, CF, S, C, D, R1, R2, L and a conversion table on the back.

- Keuffel & Esser Log Log Duplex Decitrig - A high-end American scientific rule with extensive LL scales, in its original green vinyl snap case. Marked "Copyright 1947" and "Keuffel & Esser Co." Scales include LL01, LL02, LL03, K, A, CF, CIF, CI, C, D, DI, LL1, LL2, LL3.

All four rules appear to be in good usable condition with no obvious damage visible in the photos.