DIMWIT – The Computer John Hancock Built

dodecahedraneDodecahedrane has the formula: C20H20. Every carbon atom is bonded to one hydrogen (not shown) so the molecular formula can also be written: (CH)20.

Dodecahedrane is also highly symmetric. Every carbon is physically and chemically equivalent to every other carbon. The same is true of the hydrogen atoms. This means if one hydrogen in the molecule is replaced with a chlorine (making C20H19Cl), it doesn’t matter which hydrogen you replace because the result is always the same molecule. However, if you replace two hydrogens with chlorines, or wilder yet, three, how many different isomers of C20H18Cl2 (or C20H17Cl3) could you generate?

Prof. John Hancock [chemistry 1955-1989] was interested in theoretical matters like these and it led him into a collaboration with David Digby ’57 which resulted in the construction of Reed’s first digital computer. Briefly stated, Hancock procured relays from pinball machines that the local sheriff had confiscated, Digby designed a computer that used these relays as its logic elements, and Reed students wired the whole thing together. As Digby tells the story in “DIMWIT and Doctor John” (Reed Magazine, June 2015), “It worked—sort of. It took about 5 minutes to get an answer, which was correct about 10% of the time.”

No doubt this is why John named the machine Dodecahedrane Isomer Machine With Internal Translation (DIMWIT).

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