Subsequently Murchison’s regiment joined the expedition of Sir John Moore, and participated in the disastrous retreat upon Corunna. “Murchison (writes Professor Geikie) suffered much, although he was strong and in good health, from the excessive fatigue. On one occasion, after a fruitless midnight march against the enemy, who was supposed to be advancing to the attack, Murchison, commanding that night an outlying picquet, threw himself into a corner of a farmer’s yard, and soon fell asleep. Day had scarcely broken when the cry of ‘Picquet, turn out!’ roused him from his rest, but not in time to escape the notice of the vigilant Colonel Packe, who, however, allowed him to escape with a severe reprimand. But after the halt at Tugo, when having vainly offered battle to the French, the British army retreated by a forced march to Corunna, the young lieutenant fairly broke down. The mule, which had hitherto carried himself or his kit, was lost; his old soldier servant had gone back to seek among the snow for his wife and child.” Of this sad time he has preserved the following recollections:—“Never shall I forget the night which followed the abandoning of our position in front of Tugo. We marched through that city at dusk, and then blew up the bridge, which was to check for awhile our foe. In darkness, with no food, and after sleepless nights, with worn-out shoes, and thoroughly disgusted with always running off and not fighting, this army now fell into utter disorder. Starved as they were, the men soon became reckless, and all the regiments got mixed together; in short, the soldiers were desperate, in spite of the exertions of the few mounted officers. For my own part, I walked on, usually in my sleep, with the grumbling and tumultuous mass, until awakened by the loss of my boots in one of the numerous deep cuts across the roads, which were like quagmires, so that with my bare feet I had some twenty miles still to march. Many of the soldiers got away from the road to right and left. Marching all that dreadful night my young frame at last gave way, the more so as I was barefoot, cold, and starved, and already the great body of troops had got ahead of me. In short, I was now one of a huge arrear of stragglers when day broke and the little hamlet was in sight.