The Top 40

Several years ago I saw one of those filmreels from the 40s or 50s where they had an analog electrical mechanical computer that was all gears. The different size gears each with various sprockets represented different numbers, you turned the motor on and it calculated the answer. It was interesting but the clip was too short to learn much about it.

Gears were the basis of Charles Babbage's design for the "difference engine", which he conceived in 1822. Between a combination of Babbage getting distracted by other projects and a failure to secure adequate funding, it would be almost 170 years before a working model based on his design was finally completed, to help commemorate the 200th anniversary of his birth.

Gears and shafts were indeed used both in Babbage's design and in the Differential Analyzer, but the conceptual models were very different...the Babbage design was digital, based on counting, whereas the DA was analog, based on shaft positions representing continuously-variable quantities.

A team at Marshall University has recently built a couple of differential analyzers, which they believe will be of value in teaching calculus. I think they are right, but will have an uphill fight selling a retrotech approach to an educational establishment which is always enamoured of the new and flashy.

Gears and shafts were indeed used both in Babbage's design and in the Differential Analyzer, but the conceptual models were very different...the Babbage design was digital, based on counting, whereas the DA was analog, based on shaft positions representing continuously-variable quantities.

A team at Marshall University has recently built a couple of differential analyzers, which they believe will be of value in teaching calculus. I think they are right, but will have an uphill fight selling a retrotech approach to an educational establishment which is always enamoured of the new and flashy.

My son asked for a 4 terabyte external hard drive for Christmas. It'll fit in my handbag.