Samuel Cron Cronwright had the same names as his father, the businessman, mayor of Grahamstown and member of the Cape legislative assembly, Samuel Cron Cronwright (1834-1888). Samuel the younger became a farmer, public figure, politician, and biographer of his wife, the author Olive Schreiner. He changed his surname to Cronwright-Schreiner when he married Olive in 1894, but in 1924, some years after her death, he changed it back to Cronwright when he re-married.
Cronwright was educated at St. Andrew's College, Grahamstown, and was a farmer from 1884. After his marriage the couple moved to Kimberley, and in 1898-1899 stayed for a year in Johannesburg where Samuel worked for a firm of attorneys. During the Anglo-Boer War (1899-1902) they supported the Boer cause and in 1900 Samuel visited Britain for six months to campaign against British military action in South Africa. After his return the couple moved to Hanover in the Karoo. In 1906 he was appointed Justice of the Peace in Britstown, but in 1907 he settled in De Aar. Samuel was a member of the Cape legislative assembly from 1902 to 1910. He remained in De Aar when his wife went to Europe from 1913 to 1920. After her death in 1920 he moved to Cape Town and wrote a number of books about her life, works, and views.
As part of his varied and unsettled life Cronwright-Schreiner showed a scientific interest in various agricultural and zoological matters. For example, in August 1890, when farming near Cradock, he read a paper on scab before the Cradock Farmer's Association. The paper was published in the Agricultural Journal of the Cape of Good Hope (1891, Vol. 3, pp. 117-118, 139-140, 149-150). In 1898 he produced a treatise on The Angora goat, published under the auspices of the South African Angora Goat Breeders' Association. It dealt with the introduction, development, and practical aspects of the Angora and mohair trade in the Cape Colony. The publication included a substantial paper on the ostrich which he had published in the Zoologist the previous year.
His main contributions, however, were to invertebrate zoology. In 1901 he collected spiders and scorpions around Hanover for Dr. W.F. Purcell*, arachnologist at the South African Museum. His large collection included some 50 species of arachnida that were new to the museum. Also included were a number of insects and reptiles. Purcell described the new arachnida in the Annals of the South African Museum (1903, Vol. 3, pp. 13-40), while Cronwright-Schreiner wrote a paper on "Some arachnids at Hanover, Cape Colony" for the Popular Scientific Monthly (1902, Vol. 62, pp. 145-162). During 1902 he donated Hymenoptera, especially velvet ants (Mutillidae), and other invertebrates, mammals and reptiles from the same district.
This phase of active collecting stopped as suddenly as it had begun, but he resumed collecting some years later, this time for the Albany Museum, Grahamstown. First he donated a number of tortoises in 1906. Then in 1912 he presented a large series of trap-door spiders (including a new species) and sun-spiders (Solpuga, an order of Arachnida) from De Aar. More arachnida and ants followed the next year.
In 1925 Cronwright-Schreiner published a book on The migratory springbucks of South Africa (the trekbokke) in London. He had produced a paper on the topic years earlier, which appeared in the journal Cosmopolitan in 1898/9. The book again included his essay on the ostrich. His other publications dealt mainly with political matters.