Albert Nestler, Lahr in Baden / Germany (1912) ************************************************************* VERSION (A) S C A L E S of the NESTLER » E L E K T R O « Model 37 ============================================================= Front Side Back Side ============================================================= ( 0 ... 25 cm Ruler ) V X * 1.75 (A) X^{2} ------------------------------------------------------------- (B) X^{2} S sin(0.1X) S&T arc(0.01X) (C) X T tan(0.1X) ------------------------------------------------------------- (D) Q+1 X P-1 U X * 5.24 ------------------------------------------------------------- (K) X^{3} (LL2) exp(0.1X) = keyed to SCALE A and LEFT CURSOR-MARK R E M A R K S : ( 1° = 60' ; 1' = 60" ) ============================================================= The TRIGONOMETRIC SCALES are divided in MINUTES & SECONDS The no-named scales are marked here with their common symbols in brackets: (A),(B),(C),(D),(K),(LL2). The U-Scale is folded by ( for calculating "Revol./Minute" ) π / 60 = 0.05236 The V-Scale is folded by the "Specific Resistance of Copper" sRcu = 0.0175 Ω * mm^{2} / m The CU-Marks for "Specific Conductivity of Copper" sCcu = 57.2 m / Ω * mm^{2} = 1 / sRcu The 736-Mark for 1 PS = 0.7355 kW There are 3 Versions of "Model 37" in this collection: In this VERSION (A): -------------------- The CURSOR HAIRLINES are symmetrical and in the common distance (on A-Scale) AREA/DIAMETER (on X-Scale). The LL2-Scale is UNDER the CUBIC-Scale and SHIFTED so, that CUBIC "45" is over LL2 "e". ONLY 1 SIDE-Hairline. In contrary to VERSION (B) , where ... --------------------------------------- The CURSOR HAIRLINES are NOT SYMMETRICAL and the LL2-Scale is placed OVER the CUBIC-Scale and SHIFTED, that CUBIC "39" is under LL2 "e". 2 CURSOR SIDE-Hairlines. And also VERSION (C) is different ... --------------------------------------- The SR is longer, has a red 1/X and "extended" Scales. The CURSOR HAIRLINES are symmetrical again and in the common distance (on A-Scale) AREA/DIAMETER (on X-Scale). The LL2-Scale is placed OVER the CUBIC-Scale and SHIFTED, that CUBIC "52" is under LL2 "e". 2 CURSOR SIDE-Hairlines. Historical Remarks ... The slide rule is made of mahogany with scales on celluloid veneer. On the back is a desintegrated table with constants. The cursor's side-window was missing and had to be restored. "MouseOver" the cursor in the picture to get DETAILED VIEWS. impressum: *************************************************************** © C.HAMANN http://public.BHT-Berlin.de/hamann 09/09/09 |