Pencil drawing made and presented by Miss Elizabeth Smith, of Brampton near Chesterfield, Derbyshire. This view shows the gravel-pit, the oak tree, and the Magnetic Observatory from the north-west. The oak tree, often referred to as ‘Queen Elizabeth’s oak’, fell later in the 19th century.

In 1816, the Admiralty ordered the Astronomer Royal, John Pond, to make regular observations of magnetic variation (declination). Pond’s ‘Magnetic House’, built in the Lower Garden, proved to have unstable foundations and was demolished in 1824, at which point observations ceased. Pond’s successor, George Airy, recognised the importance of magnetic work and persuaded the Admiralty to fund the establishment and staffing of a new Magnetic Observatory. Further grounds in the park were secured and an extension to the south fenced off in 1837.

Airy’s Magnetic Observatory was completed in May 1838. This drawing was made the following year. The building, which stood where the Peter Harrison Planetarium now stands, was cruciform in shape. It was built of wood on a concrete foundation, materials such as iron and brick being excluded to avoid their risk of residual magnetism.

For further views of the Magnetic Observatory, see [RGO 116/3/3], [RGO 116/3/9], [RGO 116/5/2], [RGO 116/5/6] and [RGO 116/5/9].