"Edward A. Falk" wrote in message
...
In article ,

Fun fact: when they built the difference engines from Babbage's
designs, they needed to compensate for the fact that the CNC
machine they were building it on was accurate to 1/10,000
inch but the manufacturing processes of Babbage's time were
only accurate to 1/2000 inch.

They not only wanted to know if the machine would work as Babbage
designed
it, but they wanted to know if Babbage could really have built it.
So they added 1/2000" of random noise to the CNC data before giving
the
data to the machines.


The machine was built by Joseph Clement, one of the founding geniuses
of the Industrial Revolution, who learned his skills from the great
masters Joseph Bramah and Henry Maudslay.
http://en.wikipedia.org/wiki/Joseph_Clement
"The recognised excellence of Clement's machine tools and his skill in
precision engineering led to him being employed by Charles Babbage in
1823 to work on his project to design and build his mechanical
calculating device, the difference engine."

jsw