Curtis A. Jones wrote:
>>> Keith Smillie fancied a Differential Analyzer build from Meccano
>>> parts, but found it easier just to model it.
> ...
> Here's a Meccano differential analyzer.
> http://meccano.us/differential_analyzers/robinson_da/index.html
>
> Tim Robinson, who built it, also built a couple of Babbage difference
> engines. e.g.
> http://www.meccano.us/difference_engines/rde_2/index.html
> Tim is in thick of preparations at the Computer History Museum in
> Mountain View, California, USA to show a 5-ton Difference Engine no. 2
> built by the Science Museum of London:
> http://www.computerhistory.org/babbage/
>
>
http://www.computerhistory.org/virtualvisiblestorage/popup_image.php?base_name=102637025
> It's more impressive than one might expect from the picture.
>
> If you're around London don't despair if you want to see it. The
> Babbage engine at the Computer History Museum is the second one built
> by the Science Museum and is brand new.
> Curtis
>
> P.S.
> Tim used Mathematica, with its extended-precision arithmetic, to
> generate the starting values to put into the engine to demonstrate use
> of the difference engine to make a log table which can be compared to
> one published by Babbage himself.
my goodness, that stuff is gorgeous -- thanks ever so much for these links
to the best of my knowledge, the red and green Meccano is no longer
available -- the company is now French-owned, I believe, and the colours
tend to be more (what..?) fashionable? purple and silver, for instance
IIRC, when the Science Museum built their first difference engine, they
found that Babbage's problem was not only that the required accuracy was
not available at that time, but the materials would not have been up to
the job either -- I was quite surprised that something as simple as
brass could vary so much -- and the weight! 5 tons is an awful lot of
metal to move without a proper supply of power
/phil
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