Gill's drawing shows Charles Sturt's Central Australian expedition of 1844-46, chaining the distance travelled from his base at Depot Glen to Lake Blanche, or as he believed it to be, Lake Torrens. He wished to accurately determine the distance between the lake and the Darling River. While a trigonometrical survey by theodolite would have been more accurate, this was impractical given the nature of the terrain Sturt was crossing, with no high points available to make the surveys from.

Sturt's original sketch was developed by Gill and made into a steel engraving to illustrate Sturt's Narrative of an Expedition into Central Australia, 1849, Vol.1, as frontispiece, with the title Chaining over the sand hills to Lake Torrens. The National Library of Australia titles the work The Sandy Ridges of Central Australia (possibly due to an inscription of that title on the reverse of the original artwork).

After rain in July 1845, the party moved 61 miles NW from Depot Glen, and established a new depot at Fort Grey, from where J. McDouall Stuart, Draftsman, chained a further 70 3/4 miles 75 degrees W of S direct on Mount Hopeless over sand hills. Reaching Lake Torrens on 4 August, Sturt and Stuart examined the shores to the north and to the south and determined it would be 'impracticable to proceed further'.

Chain surveying is the simplest method of surveying. Equipment consists of the survey chain, usually a Gunter's chain of 66 feet, with the individual links measuring 7.92 inches, arrows and rods and a box compass or prismatic compass. Wear and tear on the chain could result in the distance measured being slightly inaccurate. James Poole, Sturt's second-in-command on the expedition was a government surveyor and well equipped to handle this work. Sturt himself had previously and briefly served as South Australia's Surveyor General. Stuart was also a surveyor.

Charles Sturt left Adelaide in August 1844 to explore Central Australia, and determine the continent's watershed. He also hoped to unveil the secrets of the centre, and to discover the inland sea he believed existed. He took with him a boat to sail upon it. In the end, he discovered no inland sea, only the Stony Desert and the endless sand dunes of the Simpson Desert. He did however discover and name Cooper Creek, the great but ephemeral river of central Australia. James Poole died of the effects of scurvy and was buried at Depot Glen.

State Library of South Australia: Mortlock Wing. Taking it to the edge August 2004-