GK, thanks for the book list, only have a couple of them. They are full of calculus and similar and my maths simply isn't up to that.

Had a scrummage in the library and the following might be of interest. Again, more towards mechanical analogue computers or electromagnetism but if you see them for a £ (or local currency of course) or two then worth buying, I reckon anyway.

1)

Electronic Digital Integrating Computers, Digital Differential Analysers - Mayorov

2)

Electronic Computers, Principal & Application - Ivall (trivial level)

3)

Graphical & Mechanical Computation - Lipka

4)

The MIT Radiation Laboratory Series, 28 volumes but in particular

Theory of Servomechanisims - James

Computing Mechanism & Linkages - Svoboda

Components Handbook - Blackburn

Waveforms - Chance

5)

The Journal of the Franklin Institute, articles about the Bush differential analyser

These are electromagnetism books, but might have some ideas for programs to run

6)

Elementary Treatise on Curve Tracing - Frost

7)

Practical Curve Tracing - Duncan

Alternating Current Waveforms - Kemp

9)

Waveform Analysis - Manley

10)

Practical Geometry & Engineering Graphics - Abbott

11)

No particular book but equalisation of telegraph lines, under the ocean etc, not trivial!

Otherwise, I have found one of the sine/cosine pots. It is 14.4k and in a servo size 15 case. Came from a co-ordinate converter used in the navigation system (Green Satin) used in 1950s bomber aircraft, no tolerance specs but must be pretty good. The tide predictor was designed by Thompson, Lord Kelvin, in the 1890s but still can track down the article. Some in the Britannica to give a flavour.

Hope this is of some interest.