John Calladine Cockayne was the son of John Cockayne, an engineer of Hyson Green, Nottinghamshire. On 26 April 1866, he became apprenticed for a period of four years to Smith Brothers, a company of brass founders and carpenters in Nottingham.
Robert Salisbury was the son of James Moffat Salisbury of Hind's Yard, Angel Row, Nottingham. On 2 July 1874, he became apprenticed for a period of seven years to William and Albert Septimus Bradshaw, printers in Nottingham and proprietors of 'The Nottingham Journal' newspaper.
Henry Mecklenburgh was the step-son of Joseph Golland of Gainsborough, Lincolnshire. On 14 June 1889, he became apprenticed for a period of five years and seven months to Marshall Sons and Company Limited, engineers of Gainsborough, Lincolnshire