A major pertussis (whooping cough) epidemic begins…

A movement to establish a Māori king, instigated by Tamihana Te Rauparaha (son of Te Rauparaha) after having met Queen Victoria in England in 1852, has developed in response to the rapid loss of Māori land to the British government and colonists.

The movement’s proponents believe that by having a monarch who could claim status similar to that of Queen Victoria, Māori would be able to deal with Pākehā (Europeans) on equal footing.

The establishment of the monarchy is also designed to achieve unity among iwi of all regions of the islands and thus weaken the potential on the part of the British to “divide and rule”; and, in addition, it is seen as a step towards establishing law and order.

Te Rauparaha's cousin, Matene Te Whiwhi of the Ngāti Raukawa and Ngāti Toa iwi, had attempted unsuccessfully to persuade many chiefs from various iwi to put themselves forward for the position.

The elderly chief Pōtatau Te Wherowhero also expressed his reluctance, but was persuaded to accept the mantle of king at the wish of his own tribe Ngati Maniapoto.

Te Wherowhero was formally selected as king by a meeting of chiefs of the Māori tribes held at Pūkawa, Lake Taupo, in April 1857 and is crowned during elaborate ceremonies held at his marae in Ngāruawāhia in 1858.

He becomes known as Pōtatau te Wherowhero or simply Pōtatau.

The King Movement has influence over large parts of New Zealand’s North Island – in particular, the lands of the Ngati Tuwharetoa, Taranaki, Whanganui and Tainui iwi that have been involved in the movement’s establishment.

John McDouall Stuart, a Scottish-born draftsman and a member of Charles Sturt’s unsuccessful 1844 expedition to central Australia, begins the first of six expeditions to the interior in 1858.

His aim is to find minerals or new agricultural lands in the northwest of South Australia. (An area at this time unexplored, but now known to be so lacking in water and soil fertility that it remains unsettled to this day.)

Stuart takes two companions (another white man named Forster and a young Aboriginal man), a pocket compass, a watch, half a dozen horses, and rations for six weeks.

From the Flinders Ranges, Stuart travels west, ...

...passing to the south of Lake Torrens, then north along the western edge of Lake Torrens.

He finds an isolated chain of semi-permanent waterholes which he named Chamber's Creek (now called Stuart Creek, it will later become crucially important as a staging post for expeditions to the arid center of the continent.)

Continuing to the northwest, ...

Stuart reaches the vicinity of Coober Pedy (not realizing that there is a fantastically rich opal field underfoot) before shortage of provisions and lack of feed for the horses forces him to turn towards the sea five hundred kilometers to the south.

A difficult journey along the edge of the Great Victoria Desert brings Stuart to ...

...Miller's Water (near present-day Ceduna) and from here ...

...back to civilization after four months and two hundred and forty kilometers.

This expedition makes Stuart's reputation and brings him the award of a gold watch from the Royal Geographical Society.

Augustus Gregory had meanwhile been hired in September 1857 by the government of New South Wales to search for traces of Ludwig Leichhardt, the fellow explorer who had disappeared on an earlier expedition.

A party of nine was formed with Gregory in command and his brother, C. F. Gregory, as second in command.

On March 24, 1858, the expedition left Juandah, and on April 21 a tree marked with an L is found in latitude 24 degrees 35 minutes and longitude 146 degrees 6 minutes.

The Barcoo River is then followed to ...

...its junction with the Thomson.

The country is so dry on May 15 that the expedition must turn south to save the horses.

Cooper's Creek is followed until it is close to the South Australian border, ...

...coming to Strzelecki Creek on June 14.

Continuing his course mostly to the south, on June 26, he decides to proceed to Adelaide, reaching it at the end of July 1858.

Mongkut concludes trade and friendship agreements with Denmark and Portugal in 1858.