JF Ptak Science Books  Quick Post

I came upon a short notice in the Scientific American (January 30, 1892) for Louis-J. Troncet’s ingenious and very popular instant-calculator. It was a small and powerful machine  (10x6cm) that Troncet had patented in 1889, and was issued in a small book-like folding case, with the accordion folding bit containing multiplication tables. It was quick and easy to use, sold for a few dollars, and became a cheap arithmetic staple for decades. 

(I’m pretty sure that the image that appeared in Scientific American, above,  was the one used in the article by G. Mareschal, “Calculateur mecanique instante,”  in La Nature,  in 1890 (pp. 307-308).

Here’s a color image of the Troncet at the National Museum of American History:

[Source: http://americanhistory.si.edu/collections/search/object/nmah_690248  For another visit with the Troncet see the History of Computers site  http://history-computer.com/CalculatingTools/Gadgets/Troncet.html]