S2A3 Biographical Database of Southern African Science

Bosman, Mr Johannes Jacobus (surveying)

Born: 2 February 1854, Stellenbosch, South Africa.
Died: 6 March 1923, Cape Town, South Africa.

J.J. Bosman was raised on his father's wine farm in the Stellenbosch district and educated at the Stellenbosch Gymnasium. In 1874 he became the first student to pass the examination for the certificate of proficiency in the theory of land surveying, awarded by the University of the Cape of Good Hope, after a period of study at the South African College in Cape Town. His trial survey included a portion of Table Mountain and was so thorough and extensive that he was payed for the work when fully qualifying as a land surveyor in 1876. He joined Mr. Adriaan Moorrees*, surveyor at Tulbach, as a junior partner to form the firm Moorrees and Bosman, in which he practised for 16 years. Large survey tasks were entrusted to the firm by the government of the Cape Colony and Bosman performed several of them. His extensive survey of crown lands in the districts of Worcester, Tulbagh and Calvinia in 1879 was remarkably accurate and neatly documented, as shown by a partial re-survey during the secondary triangulation of the area 40 years later. In 1881 he surveyed and delimited the border between the Orange Free State (now the Free State) and Basutoland (now Lesotho), which required great tact and sound judgement to reconcile the conflicting land claims. The results were highly satisfactory and were approved by both governments.

In 1888 the government of British Bechuanaland (now part of the Northern Cape) appointed Moorrees and Bosman to determine the position of the border between that territory and German South West Africa (now Namibia). The border was defined, from the north bank of the Orange River to the 22nd parallel of South latitude, as the 20th degree of East longitude. Bosman was required to carry a chain of triangulation from a baseline measured by Lieutenant H.D. Laffan* in the Dry Harts Valley near Vryburg to the boundary line - a distance of some 470 km. Bosman tackled the task with his usual enthusiasm. He first spent some time at the Royal Observatory in Cape Town to practise astronomical observations for time, latitude and azimuth. He and H.M. Astronomer David Gill* agreed that the work should be performed with such high accuracy that it could be incorporated as an integral part of the Geodetic Survey of South Africa. Bosman arrived at Vryburg around September 1888 to start the work, which presented serious difficulties. Some of the terrain was extremely flat, requiring very large beacons some three meters high. To avoid the use of eccentric stations Bosman devised methods to place the instrument securely on top of the beacon while the observer worked on a portable platform not in touch with the beacon. The absence of water and materials to construct beacons in the thinly inhabited country also presented problems. Progress with the observations was very slow at times owing to the poor observing conditions caused by extreme heat. Astronomical observations were made at Upington and finally near Rietfontein on the boundary line in 1892. In that year the firm of Moorrees and Bosman was dissolved and in August Bosman was appointed examiner of diagrams in the office of the surveyor-general of the Cape Colony. He tackled the gigantic task of reducing his Bechuanaland observations, adjusting the results using the method of least squares, and computing the coordinates of his stations with the help of his old friend and assistant Mr. E.W. Andrews*. Much of the work was done in their spare time. The results were examined in detail by Gill, who wrote a highly complimentary letter to Bosman in March 1895 regarding the work. The accuracy of the observations proved to be equal to the best geodetic work carried out anywhere in the world, despite the difficult observing conditions. Gill also praised the methods of reduction and the astronomical determinations of latidute and azimuth and stated that, considering the difficulties involved, "one cannot sufficiently admire the energy, patience, self-sacrifice and skill with which you have carried out the work". High praise indeed.

Bosman's Bechuanaland triangulation now needed to be connected at both its eastern and western extremities to the existing chains of the Geodetic Survey of South Africa. This work was entrusted to Bosman's direction, but was carried out by the surveyor Garwood Alston* from 1898. Bosman, assisted by Andrews, reduced the observations and adjusted the triangles, completing the work in 1901. The incorporation of both Bosman's and Alston's surveys into the Geodetic Survey of South Africa amply confirmed the high quality of the work.

Bosman was appointed geodetic officer in the office of the surveyor-general in January 1903, but he was officially known as director of secondary triangulation from December 1904. He also acted as an examiner in practical land surveying. His main responsibility, from April 1903, was to direct the secondary triangulation of the Cape Colony. The initial work was carried out by officers of the Royal Engineers, who were available in the country as a result of the Anglo-Boer War, and after about three years was taken over by a number of local surveyors. The reduction of observations and adjustment to the Geodetic Survey were done by Bosman, assisted by Andrews, later by Miss Lucy Stapleton, and even by Bosman's daughter - a competent computer - at his own expense. By the time of his retirement in 1918 a belt of triangulation some 100 to 150 km wide had been completed along the entire coast of the colony, comprising 1340 stations. The work was well planned and efficiently carried out, both in the field and in the office. Bosmans's neat and extensive records were a monument to his skill and devotion to the task. However, his triangulation was based on a local Cassini-Soldner coordinate system and hence was not included in the post-1920 triangulation of the Union of South Africa. It was none the less important for cadastral control and his stations were later re-measured. He was succeeded by W.C. van der Sterr*, who received enlarged powers as director of Trigonometrical Survey of the Union of South Africa.

In 1906 Bosman delivered an extensive address on "Tertiary triangulation and traverse surveys". This was published in the South African Architect, Engineer and Surveyor's Journal in September 1906, and again as a monograph by the Institute of Government Land Surveyors of the Cape Province in 1914.

Bosman was afflicted by deafness, which became total during the last ten years of his life. Nevertheless he regularly provided assistance to numerous colleagues. He planned to write a history of survey work in South Africa during his retirement, but poor health prevented him from accomplishing this task. His artistic talent was expressed in black and white sketches, drawings, and paintings. He was an intense lover of nature, had a choice library and had a great appreciation for poetry and literature. As a person he was grave, dignified, just and generous. He was married to Bertha Moorrees.

List of sources:
Cape of Good Hope. Civil Service List, 1896.

Cape of Good Hope. Report of the Surveyor-General, 1880, 1895, 1898, 1900-1902, 1904, 1908, 1909.

Find a grave, at http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=135439709

Liebenberg, E.C. Die topografiese kartering van Suid-Afrika, 1879-1972; 'n histories-geografiese ontleding. M.A.-verhandeling in geografie, Universiteit van Suid-Afrika, 1973.

Phillips, W.W. Johannes Jacobus Bosman: A memoir. South African Survey Journal, 1924, Vol. 1, pp. 126-136.

Ritchie, W. The history of the South African College, 1829-1918. Cape Town: T. Maskew Miller, 1918.

South African bibliography to the year 1925. London: Mansell, 1979.

South African Who's Who, 1908.

Union of South Africa. Public Service List, 1914.

University of the Cape of Good Hope. Calendar, 1884-1885.

Whittingdale, W. Willem Cornelis van der Ster. 2: period 1919-1933. South African Survey Journal, 1935, Vol. 4, pp. 272-277.

Compiled by: C. Plug