Baptised 27.07.1873, died by fire at 12.5 am on 12th January 1878, aged 5 years and 8 months, with his brother Alexander Edwin, buried together in Commercial Road Cemetery, Pietermaritzburg, in Dutch Reformed and Presbyterian section, Map 1F, Section 1E, Plot 3, with tombstone.
The parents were at the theatre for the evening on a Friday and had left the house in the charge of a woman and a servant girl. The former was somewhere near but outside. At about nine o’clock the servant went into the pantry with a small oil lamp, followed by the boys. Somehow the oil-lamp was overturned [perhaps from horseplay?], and ignited a tin of paraffin so that the three were enveloped in flames. The servant somehow shut the door on the children but the explosion attracted a small crowd and the flames were extinguished as promptly as possible and the children released. But they only lingered for a few hours before expiring.
They were buried on the Sunday in the ‘Scotch’ burial ground by Rev J Gould of the First Presbyterian Church (Natal Witness Jan 15). An alternative explanation is that the attendant nursemaid had gone out of the house to rendezvous with one of the many soldiers from the garrison. The house was made from a large amount of wood and the nursemaid rushed back to find the whole room in flames so she was unable to perform a rescue. 
12 JAN 1878
Pietermaritzburg, NAT, SAF
He died in the early hours from a house fire the night before with his brother Alexander Edwin when a paraffin lamp or similar was knocked over while the baby sitter was out of the room (maybe talking to a soldier in the street) perhaps in horse play, while the parents were at the theatre on a Friday night. For years they were referred to erroneously as "the twins" (see Natal Witness etc).
↑ Source: #S2333 RUNCIMAN mailing list resources, (http://www.guernsey.net/~sgibbs/runciman/) pdf file on brothers John and William RUNCIMAN in Sth Africa, written by Mrs Mary RUNCIMAN, extracted Sep 2005 Note: 1966 information from Mrs Monica Sheena GOBLE (was the daughter of Jessie & Dr CHILD)
↑ Source: #S2567 Dth 1878 William Robert RUNCIMAN, from "A Brief History of our Branch of the Runciman Family", rcvd & extracted May 2007
It may be possible to confirm family relationships with William by comparing test results with other carriers of his ancestors' Y-chromosome or mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree: