Description
Rare and important early c.19th map showing Charles Tyers survey to fix the position of the Victorian and South Australian border.
In 1839 Tyers was transferred from the Royal Navy to the Colonial Service and given the title of ‘Commissioner for Crown Lands for Portland’ and instructed by Governor Sir George Gipps to fix the 141st meridian east longitude, the declared boundary between Port Phillip and South Australia, to ascertain in which colony the mouth of the Glenelg River was situated.
On 1 October 1839 Tyers arrived in Melbourne from Sydney on the ‘Pyramus’ and set about assembling a party which was to include Thomas Townsend, Assistant Surveyor. The party set out westwards for Portland on 13 October 1840, crossed the Moorabool River north of Geelong near Buckley’s Falls then proceeded to cross the Nuriwillum or Lea River. He then went north of Lake Corangamite and Lake Colac, unable to directly go to Portland because of swampy country, he continued northwest towards the Grampians. On the 29th he ascended Mount Shadwell and a day later Mount Rouse. The found party were faced with more by swampy land so headed north to Mount Abrupt finally arriving at Portland on 14 November 1840.
Tyers had made a triangulation and a chain traverse to Portland from Melbourne, thus fixing the longitude of Portland at 141° 35′ 52″, and made chronometer readings from Sydney and lunar observations. Taking a mean from these three calculations he fixed the meridian, but because of differing opinions on the longitude of Sydney, Captain Lort Stokes placed it 57 chains (1147 m) west and Captain Owen Stanley and Sir Thomas Mitchell at positions farther west again. Thus Tyers’s position was most favourable to South Australia. Governor Gipps wrote to the Colonial Office: ‘I have to explain that I have caused Mr Tyers’ report to be printed in order that by being circulated amongst the officers of the departments it might stimulate them to exertion, and serve as a model in future operations of this nature’. However, after long disputes the boundary was not finally settled until 1914 when documents had to be sought from Tyers’s descendants.
