Murphy, Terra incognita (1873); and F.
Long., an extent of half a million square miles, still remained a blank in the map. But the two expeditions of 1873, conducted by William Christie Gosse (1842-1881), afterwards deputy surveyorgeneral for South Australia, and Colonel (then Major) Egerton Warburton, made a beginning in the exploration of this terra incognita west of the central telegraph route.
The symmetrically placed hypothetical islands in the great continuousocean disappeared, and the oekumene acquired a new form by the representation of the Indian Ocean as a larger Mediterranean completely cut off by land from the Atlantic. The terra incognita uniting Africa and Farther Asia was an unfortunate hypothesis which helped to retard exploration.