Back to the √s
is a mechanical computing device, about
12.5 cm high, 8 cm in diameter, with
49 bits internal precision.
I'm totally in
awe about the elegance of the design and the smooth
handling. Trying to actually compute something, e.g. a
square root, on this machine, immediately makes one
aware of the roots (sic!) of numerical mathematics. There
simply is no button marked √ on the Curta, and
still people used this very machine to compute square
roots (and logs, and trigonometric functions, ...).
Until the 1980ies most scientists knew how to
efficiently compute everything on such add/substract machines,
and this knowledge is now buried without a tombstone.