From: A. Eddington, Edinburgh and the Lothians at the Opening of the Twentieth Century, Brighton and Edinburgh 1904
John McLaren was born in Edinburgh on 17 April 1831, the eldest son of Duncan McLaren MP and Lord Provost of Edinburgh, and his first wife Grant Aitken. He was of very small stature and always in delicate health so he was educated privately. He trained in Law at Edinburgh University and went on to a distinguished legal profession, details of which are given in his various biographies. He became QC, Lord Advocate, Judge of the Court of Session and Liberal MP for Wigtown and for the City of Edinburgh.
However, he had many scientific interests, botany and meteorology as well as astronomy. He was a Director of the high altitude weather observatory on Ben Nevis, set up by the Scottish Meteorological Society of which he was President. He had considerable mathematical ability and wrote ten papers for the Royal Society of Edinburgh, on equations of curves, surfaces of lenses and atmospheric refraction. He was elected FRSE in 1869 and was Vice-President three times.
Like his father, he was a supporter of the Royal Observatory and friend of Charles Piazzi Smyth, then when Smyth retired he became a member of the committee to found the new Royal Observatory at Blackford Hill and to arrange the transfer of Lord Lindsay's instruments and library from Dunecht. His legal expertise was invaluable in these negotiations. He had his own observatory but it is not certain whether it was in the garden of his house at 46 Moray Place (now the office of the Educational Institute of Scotland) or at his summer cottage at Lochailort. For a time he had in his possession the famous Dunecht Heliometer which had been used by Sir David Gill to estimate the Sun's distance, and which is now preserved at the Visitor's Centre at the ROE, and he wrote to Sir William Christie, the Astronomer Royal, wanting to borrow a photometer so that Hilger could make one for him. Biographies state that he had a "powerful telescope" but it is unlikely that he did any serious observing. He became a Fellow of the Royal Astronomical Society in 1884.
Lord McLaren was awarded the LL.D. by the Universities of Edinburgh (1882), Glasgow (1883) and Aberdeen (1906). A much respected figure and by all accounts an amusing and friendly companion he was a great friend of Professor Peter Guthrie Tait, Lord Kelvin and many other men of science. Despite further delicate health in later life he managed to reach the age of 79. He died of influenza in Brighton on 6 April 1910 and is buried in Grange Cemetery, Edinburgh. He was survived by his wife Ottilie Schwabe, three daughters and one of three sons.
[DNB; Scotsman 7 April 1910; Proc.RSE XXXI 694; Piazzi Smyth's notebooks at ROE]