The naming of Johannesburg as an historical commentary

The first recorded hint of the name Johannesburg occurs in a Sunday letter written by Capt. Carl von Brandis, and dated 3 October 1886.
What is its historical significance, and what is the relationship of this naming to the events of the time?
In a fascinating study, the author presents an original and convincing thesis. The name, given by President Paul Kruger in 1886, was only later, in 1891, ascribed to the combined names of Johann Rissik and Christiaan Johannes Joubert. Its basis in 1886 had nothing to do with either of these personalities...