William Hely Llewellyn (1849-1877) of Llewellyn and Cubitt
1878 Obituary 
WILLIAM HELY LLEWELLYN was born at Bridgend, Glamorganshire, on 20th November 1849; and after being educated at Cheltenham College, served his time from 1867 to 1870 with Messrs. R. Stephenson and Co., Newcastle-on-Tyne, passing through all the departments of the works.
He then took charge of the Wire Tramway Company's works at Lydney, Gloucestershire, for nearly a year, and afterwards of the chief works of the same company in London.
In 1872 he was engaged in erecting wire tramways at Marbella in the south of Spain.
On returning in 1873 he became manager of Messrs. Vivian and Sons' spelter works at Morriston, near Swansea.
In 1875 he commenced business on his own account, in partnership with Mr. W. Cubitt, at the Rhondda Engine Works, Pentre, near Pontypridd, which were designed and built by himself.
His death took place early in 1877, in the twenty-eighth year of his age, from a fall on a dark night over a colliery embankment, near Pentre.
He became a Member of the Institution in 1873.