KEUFFEL & ESSER, Hoboken, NewJersey / USA SN = 409093 (1952) ******************************************************************* S C A L E S of the » LOG LOG DUPLEX DECITRIG « Model 4081-5 =================================================================== Front Side [ inverse / RED ] Back Side =================================================================== [LL02] [exp(-0.1X)] [LL01] [exp(-0.01X)] [LL03] [exp(-X)] L lgX K X3 DF πX A X2 ------------------------------------------------------------------- CF πX B X2 [CIF] [1/πX] T tan(0.1X) ; [cot(0.1X)] [CI] [1/X] SRT arc(0.01X) C X S sin(0.1X) ; [cos(0.1X)] ------------------------------------------------------------------- D X D X LL3 exp(X) [DI] 1/X LL2 exp(0.1X) LL1 exp(0.01X) R E M A R K S : =================================================================== The former owner has engraved his name "J.W.FRECH" on the ends. This model is made of mahogany with scales on celluloid veneer. Impressive are the details: Look e.g. the TOP-SIDE of the SR ! It came without case and detoriated CELLULOID CURSOR-BLOCKS ... ... Had to be replaced by home-made PVC ones. Same "CELLULOID DISEASE" happened also to the DIETZGEN 1732 ... ******************************************************************* Celluloid, first produced in 1872, was the first used plastic world wide. It consists of a mix of cellulose nitrate & camphor. The plasticizer camphor is given off over time and the nitrate breaks up under the influence of oxygen & moisture and transforms to nitric acid. Both effects destroy the material - and the acid is the reason why the metal of frame and spring get brittle & rusty. Historical Remarks ... impressum: ******************************************************************* © C.HAMANN http://public.BHT-Berlin.de/hamann 10/11/12 |