|Home Up||Contact Legal Stuff|
|What a name! Yes, I know, in Spanish it simply means "The calculator"... but hey, to the untrained ear it sure carries a grand overtone, akin to that of "El Matador", or "El Conquistador"...|
This is one of the numerous calculation aids
that have sprung up to fill the simple reckoning needs of the
mathematically naïve, before electronic calculators became cheap and
ubiquitous. Slightly battered but still fully functional, it comes
from Spain, where the owner of a small antique shop dug it up for me
from the dusty back recesses of his store. He told me he's never
seen anything like it, and since I haven't either, I was all too
happy to add it to my collection.
El Calculador is a finger-thick cardboard tube 22 cm long with wooden plugs in both ends. Around the tube is a "cursor", a sliding brown paper tube that can be rotated and moved to any position on the tube. The instructions on the cursor are simple: "Se pone las cifras del tubo junta a las cifras blancas del rodillo. Entonces la resulta es visible en la ventana al otro cabo del tubo." That is, one sets the numbers on the cursor next to the white numbers on the body; the result is then visible in the window at the other end of the cursor.
Admittedly, it took me and the seller a few
minutes to figure out which numbers are which... the idea is to
juxtapose the numbers with the red background on the two parts so
they align to make a complete multiplication exercise, such as "5X9"
at the left of the leftmost photo above; the result, 45, is then
seen in the window at the right end of the cursor. Meanwhile the
"19X18" at the right, in the same photo, gives the 342 in the
left window. The other photo shows the cursor positioned to show
that 7X1=7 and 11X20=220. Basically, this is the good ol'
multiplication table, rolled up on a tube with a cursor to guide you
to the right answer, as long as it's under 19X20.
The other side of this marvel of mathematical technology can be seen in the photo below.
An antique shop in Madrid, close to the Puerta de Toledo.
Home | HOC | Fractals | Miscellany | About | Contact
Copyright © 2006 N. Zeldes. All rights reserved.