Educating youth in the habits of industry and encouraging their social advancement were important threads in the Republican agenda. Apprenticeship, the commonest form of vocational training, enabled boys to learn a useful trade and to make the vital transition between dependent wage earner and independent master. An apprenticeship in one of Philadelphia's better-known workshops was something a lad prized. Applications far exceeded available places and all firms were choosy. At William Norris in the mid-1850s 'there are always more applications for the berths than the proprietors can receive'. Middle-class lads wanted to become machinists - 60 per cent of apprentice machinists were from lower middle-class backgrounds, a higher proportion than for most other trades. In the eighteenth century apprenticeship commonly involved a formal agreement between the master, apprentice and parent. In contrast to the ambition of many apprentices, older journeymen, who had charge of the cub's instruction, might have a more jaundiced view of self-improvement.