Celebrating Mark Manning, 18th December 2009

Mark Manning is retiring from the Department to take up exciting adventures in Scotland. Lindsay Greer, James Elliott, Noel Rutter, Tony Cheetham, John Durrell and Harry Bhadeshia enjoyed his company on a snowy and bitterly cold Friday night. The evening began with drinks in Lindsay's room at Sidney Sussex, followed by dinner at the ASK restaurant.

Presentation of antique computer	Mark opens the machine
The OTIS King calculator does not require electricity	Lindsay shows his version of the manual computer
The presentation bag has both the Linux emblem and a Scottish flavour	More secrets in Lindsay's archive, the original pocket calculator made in Cambrdige
Spotted Mr and Mrs Tomohiko Hojo at the ASK restaurant	Plastic car - is this the best that plastics can do?
Nice dinner in honour of Mark Manning

Before electronic calculators, slide rules were used to do quick estimates	The accuracy of a slide rule increases with its length
This is an ingenious slide rule, short in absolute length but very accurate.	This is because the slide rule is inscribed as a spiral around a cylinder.
The central cylinder slides along the axis.	Notice the sprial. This is the top half.
The lower half.	The device was known as the OTIS KING calculator, accurate to at least three places after the decimal.
To multiply 2 by 4, the lower cursor is positioned on the 2.	The lower cursor is positioned on '2'
The top spiral is then rotated so that the upper cursor matches '1'	This is the position of the cylinder at this stage
The cylinder is then shifted upwards until the upper cursor is on '4'	The answer is revealed by the position of the lower cursor as '8'
This is the calculator with the correct positions for 2 x 4 =8