National Colonisation Society's choice in 1831 of meridians 132 west/ 141 east first borders for South Australia

An early map of the South Australia colony, extending from Fowler's Bay in the west near the 132 meridan to the 141 meridian in the east.
Image courtesy Mapco
A 32-page pamphlet, Proposal to His Majesty’s Government for founding a Colony on the Southern Coast of Australia, came from a group called the National Colonisation Society meeting in 1831 in the London chambers of solicitor William Tooke, chaired by member of parliament Colonel Robert Torrens.
The pamhlet recommended a settlement on Kangaroo Island or on the Australian mainland between the 132 and 141 meridians. Most of the society’s idea for the colony were rejected by the British government but those western and eastern boundaries were adopted.
The 1831 pamphet didn’t refer to any northern boundary perhaps because the new colony’s promoters hoped it might extend all the way north to the coast. The British colonial office picked the 26th parallel as the colony’s northern limit to curtail extravagant territorial claims. The 26th parallel was eventually fixed in 1834 during the British parliament’s debate on the South Australia colonisation bill, after previous attempts to raise it to 20th parallel and then the Tropic of Capricorn at about 23 degrees. It was suggested that “no sooner was the new colony settled after 1836 than some South Australians began to draw the boundary northwards again in their own imagination”.
The 1831 pamphlet’s choice of the 132 meridian for the colony’s western boundary (leaving a gap, filled by New South Wales, between South Australia and Western Australia) could have been influenced by navigator Matthew Flinders’ 1813 journal describing bays and features of Australia’s southern coast. The pamphlet contained Flinders’ description of Fowler’s Bay, a little east of the 132 meridian.
The coast west of the 132 meridian to the 129 meridian had the spectacular but inaccessible cliffs of the Great Australian Bight. Fowler’s Bay, near the 132 meridian, was the first protected bay where Flinders found he could go ashore. He named it after his first lieutenant. Flinders also acknowledged that his navigation east from Cape Nuyts, starting with Fowler’s Bay, marked the start of European discovery of that part of the southern coast. Dutch explorers (Captain Francois Thyssen and Peter Nutys) reached just west of that point before turning away from the coast in 1627. Similarly, the French (Admiral D’Entrecasteaux).
Flinders’ detailed description of the coastline east from Fowler’s Bay to the Spencer Gulf indicated opportunities for shipping and trading.
The reason for choosing the eastern boundary with New South Wales at the141meridian was unclear. T he 1831 pamphlet referred to explorer Charles Sturt’s discovery of the River Murray mouth, linked with the Darling River and tributaries as far as the Blue Mountains. Commercial and trading advantages were seen flowing from the River Murray, as well as access to the fertile land on Yorke Peninsula and Kangaroo Island.