in July 1858. It was through McGowan, that Todd met Joseph Oppenheimer, a German-born, British business man and inventor, who would provide assistance to Todd in his future projects, and with whom he would maintain a life-long friendship. Overland Telegraph Line In 1857 or 1859 Todd conceived the idea of the transcontinental telegraph line from Adelaide to Darwin. Most of the country in between except for the explorations of Charles Sturt and others was unknown, and it was many years before Todd could convince the South Australian government of the practicability of the scheme. In January 1863 Todd addressed the Adelaide Philosophical Society about the possibility of building telegraph routes that would link to an overseas cable. In 1868 the direct line between Adelaide and Sydney was completed and was used to determine the 141st meridian, the boundary line between South Australia and Victoria. Todd's calculations showed it to be 2¼ miles farther east than had previously been determined. This led to the long-drawn-out dispute between the two colonies. By 1870 it had been decided that the Australian Overland Telegraph Line should be constructed from Port Augusta in the south to Port Darwin in the north, though the other colonies declined to share in the cost. The southern and northern sections of the line were let by contract, and the 1000 miles in between was constructed by the department. The contractor at the northern end threw up his contract and Todd had to go to the north himself and finish it. Everything had to be sent by sea and then carted, but he met each difficulty as it arose, and overcame it successfully. The line was completed on 22 August 1872, but the undersea cable to Darwin had broken and communication with England was not effected until 21 October. After the first messages had been exchanged over the new line, Todd was accompanied by surveyor Richard Randall Knuckey on the return journey from Central Mount Stuart to Adelaide, to be met by an enthusiastic crowd. His next great work was a line from Port Augusta, South Australia to Eucla in Western Australia – a distance of – in 1876, again surveyed by Knuckey. in the 1880s, Todd's department would replace the rotting poles along the OTL with Oppenheimer's patent telescoping poles. Postmaster General of South Australia In 1870 the Post Office and the Telegraph Department were amalgamated, and Charles Todd