the south australian company's greatest source of revenue, the sale of land, had largely dried up due to surveying delays in 1838. the rapid increase in population in 1839 and 1840 due to immigration greatly added to the unemployment problem. droughts in other australian colonies in 1840, before south australia was self-sufficient in food, drove up the cost of living rapidly. gawler increased public expenditure to stave off collapse, which resulted in bankruptcy and changes to the way the colony was run. over £200,000 had been spent and the land fund in london had been exhausted. a £155,000 loan was approved by the british parliament (later made a gift) and captain george grey was sent to replace gawler, after grey promised to "maintain the strictest economy". in his time in office governor grey helped make south australia self-sufficient in terms of agriculture and restored public confidence, though the real salvation of the colony may have been the discovery of copper at burra in 1845.