Jonathan Parry writes:
On 21 December 1859 John Tyndall, a professor of natural philosophy at the Royal Institution, set out to measure the structure and movements of the Mer de Glace, a glacier above Chamonix. In previous summers he had collected data on several Alpine glaciers, but no one had ever attempted to do so in winter. He got to Folkestone but bad weather meant crossing the Channel was impossible and he returned to London. The next day, confident conditions were improving, he set off again. The snow in France was thick and he didn’t reach Geneva until Christmas Eve. He then took a diligence to Sallanches, at the bottom of the track up to Chamonix, arriving at sunset to find, to his great surprise, that there was no sledge available for the formidable night-time journey. He did manage to hire a carriage, however, whose postilion claimed he could find the way since the snow would illuminate the track. Tyndall, unconvinced by this, refused to sit inside the carriage, and instead took off his bulky clothes and perched nervously on the outside, ready to jump off if they looked likely to hurtle over the edge. Although the horses ended up in a snowdrift at one point, they reached Chamonix and its shuttered hotel late that night.