Milne double boom seismograph, 1908.
© Science Museum / Science & Society Picture Library
This seismograph was made by R W Munro after a design by John Milne (1851-1913), a brilliant English geologist who lived and worked in Tokyo, Japan. In the double boom seismograph, two horizontal pendula were carried at right angles to each other but with the booms running parallel, so the two traces could be recorded on the same roll of paper. This example was delivered by R W Munro to Eskdalemuir Observatory in 1908, and came to the Science Museum 20 years later. The cover of the boom arm asembly has been removed.