My colleague put in order not drawer in a table (as me with a slide rule), but the apartment of his dead grandmother and found ...
PS An arithmometer is Excel, a slide rule - Mathcad 
Yes, I already wrote about this devece!
My mother used this wood device (счёты - Russian abakus: считать - to calculate):
She could not only add, subtract, multiply and divide with this "computer", and take the square root!
As stated in one old book "Adding machine" (authors Evdokimov, Yevstigneyev, Kriushin) multiplication and division on the iron calculator (famous "iron Felix" - see above) is a 4 - 5 times faster than in the "wood calculator" (see above) but the addition and subtraction - 1.3 - 1.7 times slower.
I saw in my youth on the table of bookkeepers both such calculators - an Iron for multiplication and division and a wood - for addition and subtraction.
The most interesting action on the iron calculator - a division by zero. The man quickly guessed that it is not possible and stoped turning the handle. But then (middle of the last century) arithmometers with electric drive came... I heard that one such electric arithmometer is doing this devision to present time 
I saw last autumn in one store in Germany (Zittau) this cash register (see below). He was at work!
The seller gave me the possibility to pay for my purchase with this device!
