Thus the head of the inventor is kept in a state of constant turmoil.

Sometimes the whole machine has to be remodelled from beginning to end.

One step is gained by degrees, then another; and at last, after years of labour, the new invention comes before the world in the form of a practical working machine.
In 1862 Mr.Walter began in The Times office, with tools and machinery of his own, experiments for constructing a perfecting press which should print the paper from rolls of paper instead of from sheets.
Like his father, Mr.Walter possessed an excellent discrimination of character, and selected the best men to aid him in his important undertaking.

Numerous difficulties had, of course, to be surmounted.
Plans were varied from time to time; new methods were tried, altered, and improved, simplification being aimed at throughout.

Six long years passed in this pursuit of the possible.