Computer ◆ Conservation ◆ Society


December 2015

Charles Hodgson Lindsey PhD FBCS


This British Computer Society Certificate of Appreciation for Charles is the first the Computer Conservation Society has awarded.

It represents recognition by the BCS for hard work, dedication and achievement, for significant achievements and benefits as a direct result of the volunteer’s personal contribution.

The Hartree Differential Analyser is a mechanical analogue calculator built in the 1930s designed to solve partial differential equations by integration, using wheel-and-disc mechanisms to perform the integration. It was one of the first advanced computing devices to be used operationally. The design was brought to England by Douglas Hartree of Manchester University. The University acquired a full-scale machine incorporating four mechanical integrators in 1935, which was built by Metropolitan-Vickers, and was, according to Hartree: “[the] 1st machine of its kind in operation outside the United States”. Therefore the machine is very important for Manchester’s history.

Charles led the project team in working on the Hartree Differential Analyser project, towards restoring the machine to full working order.

It has been regularly demonstrated and, although only half the machine was present (the other half is on display in the London Science Museum), it is still viable.

Charles and his team were highly committed in working consistently over many years, utilising their considerable and unique experience.

Sadly the project has been terminated by the machine’s owners, MSI in Manchester. MSI has closed the Computing Gallery as part of its development plan for future galleries, and they can no longer afford the curatorial time to support the project.