Photo: University of Amsterdam Computing Museum).
The Brunsviga Nova 13, Olympia Werke AG, Wilhemshaven, circa 1920, entirely mechanical, typical of computing equipment used at Columbia University in the mid-1920s. Brunsviga and Millionaire calculators are listed in the 1924-1925 Columbia University Catalogue in the Social Science section (the specific Brunsviga models are not stated but the Nova 13 is a likely candidate).
An adding machine could do only sums. A calculator could also multiply and possibly divide (of course later calculators could do more than that). Multiplication was performed by entering the multiplicand and then turning the crank "multiplier" times (or vice-versa). Models like the Brunsviga allowed certain crank-saving techniques. For example, to multiply 567 by 32:
Here are some additional Brunsviga views, from Paula Koivunen (firstname.lastname@example.org) in Finland, April 2008, of her father's Brunsviga Nova 13, serial number 115117 (click on the thumbnails to see larger versions):
The Millionaire was a bit more efficent, requiring only one crank turn per multiplier digit; the increased efficiency was accomplished with (mechanical) lookup tables; thus it could multiply a long number by a single digit n directly, rather than by adding the number to itself n times.
See the 1933-34 section of the Timeline to learn how the laborious, time-consuming, and error-prone calculator-based methods for performing complex scientific computations prompted a Columbia Astronomy professor, Wallace Eckert, to design and build (in Pupin Hall) an electro-mechanical "network" of devices capable of automated mathematical computation under program control -- arguably the first computer.
More Brunsviga and mechanical calculator links (all working as of 27 Sep 2002):
Most recent update: Sat Apr 26 13:09:57 2008