Sydney Samuel Hough was noted for his mathematical ability from an early age. As a pupil at Christ's Hospital [School], London, he distinguished himself by gaining the Thompson Gold Medal for Mathematics in 1886, the Tyson Gold Medal for Mathematics in 1887, and an Open Foundation Scholarship at St John's College, Cambridge. He graduated at Cambridge University in 1892. During the next few years he obtained the degree Master of Arts (MA) and received further honours, including Smith's Prize in 1894, and an Isaac Newton studentship as well as a fellowship of St John's College in 1895. He devoted himself mainly to theoretical research on astronomical topics. Thus he showed that the elastic yielding of the earth could explain the Chandler period of variations in latitude, publishing the results in two papers in the Philosophical Transactions of the Royal Society of London (1895, 1896). His study of the dynamic theory of the tides, published in the same journal (1897-1898), is said to have constituted the most important contribution to the topic since the time of Laplace (Obituary, 1923). He introduced the effects of the mutual gravitation of the ocean and dealt with both the free and forced oscillations of the oceans.
In September 1898, following the retirement of W.H. Finlay*, Hough was appointed chief assistant to Dr David Gill*, Director of the Royal Observatory, Cape of Good Hope. He arrived for duty towards the end of October. Here his lack of experience in practical astronomy was soon rectified and recognition of his contributions to astronomy followed. In 1899 he was elected a Fellow of the Royal Astronomical Society, in 1902 a Fellow of the Royal Society of London, and in 1905 received the Hopkins Prize of the Cambridge Philosophical Society for the most important memoir of a mathematico-physical nature published by a graduate of the university during the three preceding years. He married Gertrude Annie Lee, vice-principal of the Good Hope Seminary in Cape Town, in March 1906. They had no children and she died during the influenza epicemic in 1918.
During Gill's visits to England in 1900 and 1904 Hough was left in charge of the observatory and proved that he had the administrative skills required to succeed Gill as Director. This came to pass when Gill retired in February 1907. The now vacent post of chief assistant was filled by Dr J.K.E. Halm*.
During his directorship Hough continued the programme initiated by Gill to improve star positions in the southern hemisphere, using mainly the new reversible transit circle and the astrographic telescope. The results were published in several extensive catalogues: Fundamental catalogue of 1293 stars for the equinox 1900, from observations made at the Royal Observatory, Cape of Good Hope (1915); Fundamental catalogue of 1846 stars for the equinox 1900... (1920); Cape astrographic zones. Catalogue of rectangular co-ordinates and diameters of star images derived from photographs taken at the Royal Observatory, Cape of Good Hope... (11 volumes, 1913-1926); and some volumes of the Results of meridian observations of stars made at the Royal Observatory, Cape of Good Hope.... He particularly enjoyed the extensive calculations that this work involved. His other projects included a detailed investigation of the division errors of the reversible transit circle (published in the Monthly Notices of the Royal Astronomical Society in 1904) and a long series of observations during 1905-1921 of the major planets, with the heliometer (Annals of the Cape Observatory, 1911, 1923). He published a complete discussion of the heliometer triangulation of the stars near the celestial South Pole and folllowed this up by photographic triangulation of the same region, thus deriving highly accurate star positions (Annals of the Cape Observatory, 1914). In 1910 a programme of daily photographs of the sun was initiated, and in 1913 a series of experiments to determine the brightnes of stars more accurately from photographs taken with the astrographic telescope. When the International Astronomical Union was formed he was elected chairman of the Committee on Fundamental Astronomy. In 1922 he attended the meeting of the Union in Rome, where he was elected British vice-president of the Union for a three year term.
Hough became a member of the South African Philosophical Society in 1899, served on its council in 1906 and was president in 1907. When it became the Royal Society of South Africa in 1908 he became one of its first fellows and served as its first president for four years in succession. Thereafter he was regularly elected as a member of its council. He also joined the South African Association for the Advancement of Science as a foundation member in 1902; the next year, and again in 1908, he served on the committee for Section A (which included astronomy). From 1906 to 1908 he was a member of the Meteorological Commission of the Cape of Good Hope. At the foundation of the Cape Astronomical Association in November 1912 he was elected honorary president, and presided at the association's inauguration on 13 December that year, when the president, J.K.E. Halm, delivered his inaugural address. Ten years later the Astronomical Society of South Africa was formed, with Hough as its first president.
Though he was a shy and reserved person, those who knew him well found that he had a genial nature. Except for his role in scientific societies and playing some golf and tennis he did not participate actively in public life. Early in 1923 he became ill with cancer. An operation failed to halt its progress and he left for England in March that year to seek further treatment. He died at the home of his brother near London.