Albert Nestler, Lahr in Baden / Germany (1925) ****************************************************************** S C A L E S of the N E S T L E R » RIETZ « Model 23 ================================================================== Front Side Back Side ================================================================== ( 0 ... 25 cm Ruler ) K X3 A X2 ------------------------------------------------------------------ B X2 S sin(0.01X); sin(0.1X) C X T tan(0.1X) ------------------------------------------------------------------ D X L lgX ( 1:25 Ruler ) R E M A R K S : ( 1° = 60' ; 1' = 60" ) ================================================================== The TRIGONOMETRIC SCALES are divided in MINUTES(') & SECONDS(") S keyed to A/B ; T keyed to C/D On the back side is a ( worn-out ) table with physical constants. In the INNER BODY of this historic mahogany RIETZ SR are 2 PATENT- NUMBERS engraved 173660 (=Nestler,1905) & 181110 (= M.Rietz,1902), and NO MODEL NUMBER ! But the SR came in a cardboard case with the INSCRIPTION » No.23 Nestler's System Rietz D.R.P. No.173660 « The CURSOR GLASS was broken. It had to be replaced by a HOME-MADE of PVC from a CD-Cover - The HAIRLINE is made with a sharp »X-ACTO« and colored with a permanent marker. "MouseOver" the cursor in the picture above to get a DETAILED VIEW of it ... Historical Remarks ... impressum: ****************************************************************** © C.HAMANN http://public.BHT-Berlin.de/hamann 06/20/11 |