BGS ran a series of Rubidium Vapour magnetometer stations, mainly in the UK, but also overseas. Data is held on 3 batches of CDs. The largest batch consists of 20CDs containing data from 1977 to 1984. The second batch contains a duplicate of the 1980 data, but also contains documentation and software to read the data files. The final batch is a single CD holding data from 1976 (a time when the stations were being set up). Data was sampled at 2.5sec intervals.