JF Ptak Science Books Quick Post
The small $25 miracle/godsend to number crunchers everywhere was this small, nine-place, sliding-digit chain-adder mechanical calculator, set in nickel-plated metal, and which we see in this fantastic and half-bizarre ad in Illustrirte Zeitung for June 1922. The instrument was about eight inches long and came in its owns hard case, and was a very good instrument for the lowish-end market. The add of course is fantastic. (“Die Erloesung” could I guess be transliterated as “Deliverance!” from the drudgery of making calculations by hand.)
