Under the stairs in the school house at Shelsley was a large cupboard full of interesting memorabilia, notably what my dad had from his army years. At the end of WW II he had become a major and soon I found his hat, swagger stick (which I still have) and a bugle. There was also a gun holster but no gun inside (thankfully). He best discovery was his slide rule and, patient man that he was, he taught me how to use it.
Slide rule.
It was described as a “mechanical analog computer” so I guess the abacus was the very first analog computer when you think about it. I have only a dim recollection of how the slide rule worked but I played with it for several years. I wondered whether my dad had used it to target g=his guns (he was in the Royal Artillery) but I never got round to asking him. The Wikipedia article describes what a slide rule can and cannot do, but at school we had moved on to log tables for calculations. Later, in 1973 I was at University College London on my first PostDoc and together with a few others I was asked to tutor some students for a term. My reward was some £80 which I (and also a few colleagues) used to buy our first Sinclair pocket calculators.
Oh the excitement! Today that £80 is worth €1100 ($1200) but in 1973 it was worth its weight in gold. And you needed a lot of gold to buy the batteries which had a very short life – but you did have a new toy! (Sir) Clive Sinclair was a remarkable man. He was a self-taught pioneer in electronics and the first on the market with (at the time) very imaginative new gadgets. Much of what he dreamt up and brought to the marketplace was soon replicated by the larger science-based companies. Much later I would buy a Seiko watch with a calculator function with input from figures your provided by your finger on the screen. Of course, this was just a gimmick.
Perhaps the craziest Sinclair invention was his battery driven car. It was largely invisible to trucks and there were many accidents. Here in the Netherlands there are hundreds of bicycles where the cyclist lies almost horizontal – but here there are cycle lanes and all drivers live in fear of hurting a cyclist.
Now let’s end in the early 80’s with my Texas Instruments scientific calculator which was so hip that you wanted everyone to see you had one. There was even a special pouch which you could attach to your belt and allow a few centimetres to be visible under your jacket! This picture is all I could find of this pouch and a pouch user – the gun-holster similarity is rather obvious here.
If you Google Clive Sinclair you will pick up quite a few stories of his private life which was far from dull. He was ahead of his time in so many ways and yet also very wary of the Internet and not a user of Email. He was about more than just numbers…
dickwife 
Most interesting reference to the work of Sir Clive Sinclair. For the last couple of years before I retired I worked as a lecturer in Horticulture, Countryside Management and Agriculture at a college in Milton, just north of Cambridge. Just up the road was Milton Hall which was built for a man called Knight in about 1720. The gardens were the first piece of work by the renowned landscape designer Humphrey Repton. Sadly the landscape has partly been built on, the rest being overgrown but there are moves afoot to restore it. Sinclair had both his home and his laboratory in the hall during the 1970s and 80s. Today the hall is let as office suites to a wide range of businesses.
Bob Greef