Henry Georges (originally Henri-Georges) Fourcade, botanist, forester and surveyor, received his schooling in Bordeaux and was awarded the diploma of the Ecole Superieure de Commerce et d'Industrie (High School of Commerce and Industry) in 1880. He came to the Cape Colony with his divorced mother and sister that same year and in 1882 passed the examination in land surveying of the University of the Cape of Good Hope. In July that year he was employed in the newly created Department of Forestry in Cape Town under the Frenchman Count M. de Vasselot de Regne*, who gave him some training and put him in charge of the forest herbarium. Early the next year he was transferred to Knysna and in 1886 was promoted to district forest officer there. In that year he did his first topographical survey, in the Milwood area.
In February 1889 Fourcade, at the tender age of 23, was sent to Natal to advise on the establishment of a Forestry Department in that colony. He soon submitted his Report on the Natal forests (Pietermaritzburg, 1889), which contained original information on Cape timbers and valuable recommendations, was widely praised, and led to the creation of a forest service in Natal in 1891. After his return to the Cape in May 1890 he became acting demarcation officer for the Midlands Conservancy, with the task of carrying out forest surveys. Only in 1892 did he pass the practical survey examination set by the surveyor-general's office, and then submitted the necessary trial survey to be formally authorised to practice as a land surveyor in 1894. In carrying out his surveys of the southern Cape forests, in which he was actively engaged from 1891, he built his own beacons and signals of an improved design and set up a trigonometric network that eventually covered 39 000 square kilometers. By 1898 his survey of the coastal districts from north of Mossel Bay eastwards to beyond Plettenberg Bay was nearing completion. It was of such a high standard that it formed a valuable extension of the triangulation of the Cape Colony. He did at least some of the reductions of the observations himself, using rigorous adjustment methods. A few years later, during September 1902 to January 1903, he carried out part of the secondary triangulation of the colony around Alexandria and Albany, and was recognised for the quality of his work.
In June 1892 Fourcade became a member of the South African Philosophical Society and that same year read his first paper before the society, "On the repetition of angles", published in its Transactions (1893, Vol. 7, pp. 63-76). This was followed a few years later by "Notes on the three point or Pothenot's problem" (Transactions, 1898, Vol. 9, pp. 51-53). Around this time he began to develop an elementary form of stereoscopic photography to analyse distant topography and on 2 October 1901 read an historic paper, "On a stereoscopic method of photographic surveying" before the South African Philosophical society. It was published in the Transactions (1903, Vol. 14, pp. 25-38) and overseas in Nature (1902). The reading of his paper predated the publication in 1902 of a similar paper by Dr C. Pulfrich of Jena, who is generally credited with discovering the theory of stereophotogrammetry. In his paper Fourcade independently established a theory of three-dimensional measurement and gave details of his design of a surveying camera and a measuring stereoscope employing the reseau system of measuring image co-ordinates. After having these instruments made in England he took stereoscopic photographs from the ends of a 340 m baseline in the vicinity of Signal Hill, Cape Town, in August 1904 and produced a topographic map of Devil's Peak - the first significant application of stereoscopic measurements to topographic surveying in southern Africa and perhaps in the world, though a similar exercise seems to have been undertaken at the Austrian Military Geographic Institute at about the same time. The next year he read a paper, "On instruments for stereoscopic surveying" before the joint meeting of the British and South African Associations for the Advancement of Science in Cape Town, in which he described the construction and operation of his instruments. He intended to publish a more complete account later, but seems to have lost interest in the subject for the next 20 years.
Fourcade was promoted to forest surveyor in 1902 and transferred to Cape Town. Two years later C.L.H. Max Jurisch* retired as Surveyor-General of the Cape. Even though Fourcade was a brilliant and senior surveyor in government service he did not get the post, mainly because he was seen as lacking in the tact and interpersonal finesse required for such an important position. Instead, he was allowed to retire with full pension rights in February 1905 (at the age of 39!) and his post abolished. He retired to a secluded existence on his farm Ratel's Bosch (later part of the Lottering State Forest), but in 1913 moved to Witte Els Bosch (now Witelsbos). Here he set up a saw mill and sold wood from his farm, with substantial financial success.
For some reason Fourcade ended his membership of the Philosophical Society of South Africa around 1899, but joined up again in 1901. He remained a member when it became the Royal Society of South Africa in 1908. Meanwhile he had also joined the British Association for the Advancement of Science in 1903.
Around 1920 he came out of his self-imposed isolation and began to participate more actively in public life, rendering assistance to the Botanical Survey of the Eastern Cape. He had started his private herbarium in 1905, collecting mainly in the districts of George, Knysna, Humansdorp and Uniondale, and became the principal authority on the flora of the region. He did many of his own identifications, but also received assistance from Mrs H.M.L. Bolus* and the Bolus Herbarium. He described some 34 of the species that he discovered in the Transactions of the Royal Society of South Africa (1934, Vol. 21, pp. 75-102). His excellent Checklist of the flowering plants of the Divisions of George, Knysna, Humansdorp and Uniondale was published in 1941 as Memoir No. 20 of the Botanical Survey of South Africa. It listed some 3000 species, including 16 named after him by other botanists. Examples are Oxalis fourcadei, Erica fourcadei, Carpobrotus fourcadei, Phylica fourcadei, Babiana fourcadei and Watsonia fourcadei. His last important botanical publication was his "Notes on Burchell's Catalogus Geographicus", in the Journal of South African Botany (1944), which served to fix the exact localities of some of W.J. Burchell's* famous collections.
After a visit to Britain in 1925, during which he questioned the way European photogrammetrists approached the problem of aerial surveying, he developed the theory of relative orientation which underlies modern photogrammatic theory and the design of photogrammatic plotters. His work was published in a series of eight papers in the Transacations of the Royal Society of South Africa in 1927-1930 (Vol. 14, pp. 1-112; Vol. 16, pp. 1-22; Vol. 17, pp. 21-22; Vol. 18, pp. 237-246). The theory was applied in the design of what he called a Steriogoniometer, a prototype of which was financed by the British War Ministry and which proved his theory in practice. However, again he received little or no international recognition. Returning to the problem a decade later at the age of 75, he designed a simplified stereoprojector. Although it was not produced commercially it was perhaps his greatest invention. He described it in "A projection method of mapping from air photographs", which appeared in the Empire Survey Review (1940) and in the Transactions of the Royal Society of South Africa (1940, Vol. 27, pp. 270-275).
Although he was never a farmer, Fourcade had an interest in agriculture. In 1904 he published an article on "Sour soils and their treatment", dealing with drainage, liming and manuring of the soil, in the Agricultural Journal of the Cape of Good Hope (Vol. 25, pp. 33-43). Another of his interests was the measurement of rainfall, which led him to design a special rain gauge to record the direction and inclination of rain. The instrument could also be used to estimate the moisture in the form of fine drops carried by air currents in misty weather. He also published "Some notes on the effects of the incidence of rain on the distribution of rainfall over the surface of unlevel ground" in the Transactions of the Royal Society of South Africa (1942, Vol. 29, pp. 235-254). His other interests included history, geology, archaeology, monetary policy and poetry, and he corresponded with leading scientists in several of these fields. In 1927 he was elected a Fellow of the Royal Society of South Africa, and he was an honorary vice-president of the South African Forestry Association.
Fourcade remained a bachelor and left his entire estate to the University of Cape Town, though his Africana collection was donated to Rhodes University College a year before his death. His collection of plants went to the Bolus Herbarium. In recognition of his contributions to science honorary Doctor of Science (DSc) degrees were conferred on him by the University of Cape Town in 1930, and by the University of South Africa (through Rhodes University College) in 1947. He was a man of superior intelligence, great inventive ability, and high principles; a perfectionist; serious, with little sense of humour; with the charm, wit, and fiery temper of a Frenchman.