Guest author, Stephen Gillam-Smith BSc CEng MIET (Great-Grandson of Charles and Alice Todd)

Alice Springs was named after the wife of Charles Todd who, in 1873, was elected a Member of the Society of Telegraph Engineers, the predecessor of today’s IET. His election reflects the Society’s growth internationally and Todd’s success in connecting Australia to the rest of the world 150 years ago.

Sir Charles Todd’s membership application to the Society of Telegraph Engineers

Todd joined the Royal Observatory at Greenwich as a ‘boy computer’ and 14 years later became responsible for the galvanic department, transmitting time signals. His expertise led him to be appointed Superintendent of Telegraphs for the Colony of South Australia.

Before setting sail with his bride Alice in 1855, he declared his ambition to establish a telegraphic link between Australia and England; however, he had to wait until 1870 before a private company planned a submarine cable linking Darwin to Java and thence to London. South Australia’s offer to build a 3200km line to connect Darwin to Adelaide was accepted, but it had to be operational by the end of 1871.

With just 18 months to construct the line, Todd organised teams to plant about 30,000 poles across the unknown centre of Australia. He divided the task into three main sections. Unexpectedly the northern section, and not the dry red centre, proved to be the most challenging. Tropical rain during the wet seasons made the tracks impassable, cutting off the construction teams from supplies of materials and food.

In January 1872, facing potential disaster, Todd travelled to the Northern Territory to manage the logistics in person. The politicians had wanted all materials to be shipped via Darwin but, by using the Roper River, Todd reduced the supply route by 320km. He even diverted an ocean-going ship, the Omeo, complete with her passengers, 130km up the river to unload her cargo directly at the distribution depot.

Reproduced with the permission of Parks and Wildlife, Northern Territory Government

On 22nd August 1872 the Overland Telegraph Line was finally completed: Adelaide was connected to Darwin but not to Java, the submarine cable having failed; fortunately for Todd and the Government, the penalties for delays were soon forgotten.

Todd used technology proven on the other lines installed in Australia; a single 8 SWG galvanized iron wire with a pole every 80 metres operating at 120 Volts from Meidinger cells located at the repeater stations. Initially most of the poles were cut from local trees however the termites feasted on them so, in time, they were replaced with iron ones. During dry weather the Morse-coded messages could be transmitted all the way, without it having to be re-keyed, enabling a reply to be received in seconds.

Farmers were the first to benefit as, even at 9s 4d per word (in 1873), the Overland Telegraph enabled them to negotiate better prices for their wheat and other exports before shipping.

Although known as Telegraph Todd, Sir Charles was a polymath. He was also Southern Australia’s Government Astronomer, Postmaster General and the Government’s technical expert. His records of meteorological observations over 30 years are of significant value to today’s climate scientists.

To mark the 150th anniversary of the Overland Telegraph a website, ot150.net celebrates the achievement of the team that constructed the line.

Image Credit:

Feature image of Sir Charles Todd and Alice Todd reproduced with permission from Stephen Gillam-Smith BSc CEng MIET and State Library of South Australia (reference B 69996/9).