Files N30/17 to /30. Desk calculating machines, The National and other Accounting Machines, The Log-A-Bax Accounting Machine. Modifications to circuits, F. Colebrook. Programming and coding for the Pilot ACE by J.H. Wilkinson. Uses of the ACE (NPL High Speed Computer) Also "The work of Mathematics Division" ACE Programmes and notes on maintenance. Laplace's equation by relaxation, forward integration, method of characteristics for vibrating string. etc.