Footnotes

• During the 1840s Professor Edward Forbes, later Professor of Natural History at Edinburgh University, formed the 'Azoic Theory' based upon observations made on a dredging voyage aboard H.M.S. Beacon between 1841-1842. This theory stated that there was a depth limit to the distribution of life in the sea, a view that remained prevalent until the late 1860s, when the work of the Norwegian scientist, Michael Sars, challenged it. Prompted by this, Charles Wyville Thomson (a student of Forbes) instigated the cruises of H.M.S. Lightning and H.M.S. Porcupine through the deep waters north and west of Scotland, which were funded by the Admiralty and the Royal Society. The Porcupine set sail in May 1869 on the first of four cruises. During the second voyage, working in the Bay of Biscay, Captain Calver achieved the unprecedented feat of dredging to a depth of 2,435 fathoms (14,610 feet). Thomson used the results of his findings to organise the ambitious three and a half year global voyage on H.M.S. Challenger (1872-76) cited in any text on the study of deep-sea biology