1957 was designated International Geophysical Year, generating interest in such questions as "What is the mass of the Earth?"  

The first successful answer to that question was given in 1774, by an experiment first suggested by Newton and carried out on Schiehallion, a mountain in the centre of Scotland.

During 1957, Dick gave a talk about that experiment in a number of places (probably to meetings of the Scottish branch of the Institute of Physics).  John Little remembers hearing it in the old Glasgow Royal College of Science and Technology (now Strathclyde University).  There is no extant copy of the text of those talks.  

The typescript which our son found in the junk heap dates from that year, but it does not include the reference John remembers, to "an (earth-shaking!) rebellion going on all around".  Dick tells me that it was a proposed 15-minute script which was not, after all, broadcast.

Some years later, 1962 or 1963 probably, he gave a lecture on the same topic (but not the same lecture), for senior school-children in Edinburgh.  I remember hearing it, and being disappointed because it had less discussion of the Scottish social context than did the 1957 lectures, but it was enlivened by more slides and overhead projector transparencies.  Michael Smyth, who joined the Astronomy department in the early 1960s, remembers hearing Dick talking on the topic to the student Physical Society in 1962.  He was inspired to make a family expedition to Schiehallion to look for the evidence, and gave Dick some of the slides he took there. We are indebted to Mike for letting us use them here.  He retains the copyright.  He has maintained a strong interest in the mountain ever since.

Dick had explored the north face of the mountain before his 1957 lectures, along with Chris Carter, architect and watercolourist, whose brother Michael Carter had been Dick's research assistant after graduating in the early 1950s.  They took some photographs then, but we have not been able to find them.

Dick's final version of Maskelyne on Schiehallionwas prepared in 1990, at the request of Leslie Barr, for a meeting of the Glasgow Royal Philosophical Society.

In 1999 ownership of the eastern part of the mountain passed to the John Muir Trust.  You can find out a lot more about it on the Trust's website, and buy superb postcards and pictures from their on-line shop.

To make the slide showing the position of Schiehallion, Dick pinned two white tapes to a crude blue card 'map' stuck on our dining-room wall.  This puts the earliest date for the talk for senior schoolchildren at 1961, when we moved to our new house, and the latest date before 1964 when there would have been too many postmarks pinned to the 'map':