Alexander Armstrong (Royal Navy officer)

Sir Alexander Armstrong KCB FRS (c. 1818 – 4 July 1899) was an Irish naval surgeon, explorer, naturalist and author. After obtaining a medical degree he joined the Royal Navy and was stationed on board HMS Investigator, tasked with finding the lost expedition of explorer Sir John Franklin. Investigator was trapped in the ice at Mercy Bay in 1851 and Armstrong spent several winters in the Arctic before he returned to London.

Armstrong's account of the voyage, Personal narrative of the discovery of the north-west passage, was published in 1857. It won the Gilbert Blane gold medal for the best journal kept by a Royal Navy surgeon. He also published a second book entitled Observations on naval hygiene and scurvy, more particularly as the latter appeared during a polar voyage. He continued in a career with the Royal Navy, serving in the Baltic Sea during the Battle of Suomenlinna. He was also superintendent of hospitals in Malta and England and he became director-general of the Royal Navy's medical department in 1869. He was knighted into the Order of the Bath in 1871.