I showd my students a virtual slide rule as example of analogue computer.  Became fascinated with them and just bought a Faber Castell 52/82, duplex with 19 scales; of course from ebay.  Not got it in the post yet.  As a kid I used 4 figure tables but in O'Level class I was allowed to use my brand new TI-30. Didn't get taught slide rule.  I liked the LL scales, raising e^x. I new there had to be a way to have y instead of e, so I looked up raising arbitrary y by arbitrary x.  Well cool! www.antiquark.com