William M. Worssell, astronomer, joined the civil service of the Transvaal Colony in July 1901, while the Anglo-Boer War (1899-1902) was still in progress. He worked in the Post Office, had a knowledge of telegraphy, and was a keen amateur astronomer. In 1909 he was appointed as assistant astronomer at the Transvaal Observatory in Johannesburg, directed by R.T.A. Innes*. He brought with him a 100 mm telescope which was housed at the observatory during his entire career. After the formation of the Union of South Africa in 1910 the observatory was renamed the Union Observatory and its staff re-appointed (in April 1912), with Worssell as scientific assistant. In 1915, during World War I (1914-1918), he tried to enlist for military service, but was rejected because of his myopia (short-sightedness). He remained at the observatory until his retirement in November 1936.
Much of Worssell's time was devoted to managing the observatory's time service, but he was also involved in other activities. In September 1910 he, Innes, H.E. Wood* and Mrs Wood observed the so-called Gegenschein (counterglow) - a very faint patch of light, visible only on clear moonless nights, on the ecliptic directly opposite the position of the sun - and described their observations in Circular No. 5 of the Transvaal Observatory.
Worssell was a Fellow of the Royal Astronomical Society. In 1918 he gave a lecture before the newly established Johannesburg Astronomical Association. Subsequently he played an active role in the Astronomical Society of South Africa (founded in 1922), serving on its first council (1922-1923), as joint vice-president for 1924/5 and as a member of council again for 1928/9 and 1929/30. He was also a member of the committee of the society's Johannesburg Centre for most years from 1923 to1934 and its chairman for 1924/5. During 1923/4 he was director of the society's Variable Star Section and contributed a paper on "The observation of variable stars" to its Journal (1924, Vol. 1(3), pp. 75-78).
Worssell was not married.