This land mass included the islands of Jura and Islay and was probably connected to the mainland of Scotland by an isthmus near Loch Craignish, south of Oban.

[7] Submarine surveys indicate that the rock is at the eastern end of a valley stretching 80 miles (130 km) into the Atlantic, which may "account for the seemingly abnormal seas to which the tower is subjected".

The author Robert Louis Stevenson wrote: An ugly reef is this of the Dhu Heartach; no pleasant assemblage of shelves, and pools, and creeks, about which a child might play for a whole summer without weariness, like the Bell Rock or the Skerryvore, but one oval nodule of black-trap, sparsely bedabbled with an inconspicuous fucus, and alive in every crevice with a dingy insect between a slater and a bug.

[15] Between 1800 and 1854 thirty ships were wrecked on the reef;[16] however, the requirement for a lighthouse was not only to warn seafarers away from Dhu Heartach itself, but also to guide them past the fearsome Torran Rocks, which lie between the Ross of Mull and Colonsay.

Originally it was considered to be an impossible site for a light, but the loss of the steamer Bussorah with all thirty-three hands on her maiden voyage in 1863 and of an astonishing 24 vessels in the area in a storm on 30–31 December 1865 encouraged positive action under pressure from insurers Lloyd's of London and a Captain Bedford of the Admiralty.

Fourteen miles distant from Dhu Heartach across open sea, the little island provided a granite quarry and a shore station once the work on the lighthouse was completed.

It held firm, although fourteen men including Brebner were trapped there for five days, and at one point seawater poured in through the trapdoor, swirled around them and exited with their remaining food supplies.

[16] Describing a similar occasion, R. L. Stevenson wrote: The men sat high up prisoned in their iron drum, that then resounded with the lashings of the sprays ...

Masonry work was completed in 1871 and the lantern, optical apparatus and fog bell installed the following year, Dubh Artach becoming the first isolated rock light in Britain to use paraffin.

If full justice were to be done, the list should be much longer, but I can only add that out of all the workmen who took their lives in their hand to finish the Dhu Heartach Lighthouse, there were very few who turned poltroon.

Despite the exceptionally adverse conditions faced by the keepers, which resulted in them receiving additional payments in kind, Ewing was not the only one who served the light for a decade or more.