Collie's professional career was spent as a scientist but his
avocation was mountaineering. Among mountaineers, he is perhaps best remembered for his pioneering climbs on the
Cuillin in the
Isle of Skye, but he also climbed in the English
Lake District and in the Alps with
William Cecil Slingsby,
Geoffrey Hastings and
Albert F. Mummery. There are alpine connections in Collie's family, his aunt was elected to the Alpine Club in 1861, and his uncle, Stephen Winkworth (1831-1886), He is also remembered in ''Collie's Ledge'', a famously exposed rocky scramble across the west face of Sgùrr Mhic Choinnich, (MacKenzie's Peak) which is named after his great friend. Since the first traverse of this ledge was made by MacKenzie with the Irish climber, Henry Hart, rather than Collie himself, some authoritative publications have begun to use the name ''Hart's Ledge'' In the 1997 BBC TV series on Scottish climbing,
The Edge, Collie and MacKenzie's exploits were re-enacted by Alan Kimber (Collie) and John Lyall (MacKenzie). Collie also made significant ascents on mainland Scotland, notably the first ascent and first winter ascent of
Tower Ridge on
Ben Nevis with Godfrey Solly and J. Collier on 29 March 1894. The ridge had one previous descent by the Hopkinsons in 1892. In 1894 he also climbed the eponymous Collie's Pinnacle on
Bidean nam Bian, Argyll's highest hill, by its short side. (10 metres, grade Easy) In 1895, Collie, Mummery, and fellow climber
Geoffrey Hastings went to the
Himalaya Range for the world's first attempt at a Himalayan 8,000-metre peak,
Nanga Parbat. They were years ahead of their time, and the mountain claimed the first of its many victims: Mummery and two
Gurkhas, Ragobir and Goman Singh were killed by an
avalanche and never seen again. The story of this disastrous expedition is told in Collie's book,
From the Himalaya to Skye. After gaining climbing experience on the
Alps, the
Caucasus and the
Himalaya, in 1897 Collie joined the
Appalachian Club upon the invitation of
Charles Fay, and spent the summer climbing in the
Canadian Rockies. From 1898 to 1911, Collie visited the Canadian Rockies five more times, accomplishing twenty-one
first ascents and naming more than thirty peaks. He was particularly interested in locating and climbing the mythical giants of
Hooker and Brown which had bordered the forgotten fur trade route through the Rockies and were reputed to be over 16,000 feet high. In 1903, Collie and Hugh Stutfield published an authoritative book on the region,
Climbs and Explorations in the Canadian Rockies. ==Death==