Fox of Derby, Roberts of
Manchester, Matthew Murray of Leeds, Spring of Aberdeen, Clement and
George Rennie of London; and there may be other claimants of whom we
have not yet heard. But most mechanical inventions are of a very
composite character, and are led up to by the labour and the study of a
long succession of workers. Thus Savary and Newcomen led up to Watt;
Cugnot, Murdock, and Trevithick to the Stephensons; and Maudslay to
Clement, Roberts, Nasmyth, Whitworth, and many more mechanical
inventors. There is scarcely a process in the arts but has in like
manner engaged mind after mind in bringing it to perfection. "There is
nothing," says Mr. Hawkshaw, "really worth having that man has
obtained, that has not been the result of a combined and gradual
process of investigation. A gifted individual comes across some old
footmark, stumbles on a chain of previous research and inquiry. He
meets, for instance, with a machine, the result of much previous
labour; he modifies it, pulls it to pieces, constructs and reconstructs
it, and by further trial and experiment he arrives at the long
sought-for result." [15]

But the making of the invention is not the sole difficulty. It is one
thing to invent, said Sir Marc Brunel, and another thing to make the
invention work. Thus when Watt, after long labour and study, had
brought his invention to completion, he encountered an obstacle which
has stood in the way of other inventors, and for a time prevented the
introduction of their improvements, if not led to their being laid
aside and abandoned. This was the circumstance that the machine
projected was so much in advance of the mechanical capability of the
age that it was with the greatest difficulty it could be executed.
When labouring upon his invention at Glasgow, Watt was baffled and
thrown into despair by the clumsiness and incompetency of his workmen.
Writing to Dr. Roebuck on one occasion, he said, "You ask what is the
principal hindrance in erecting engines? It is always the smith-work."
His first cylinder was made by a whitesmith, of hammered iron soldered
together, but having used quicksilver to keep the cylinder air-tight,
it dropped through the inequalities into the interior, and "played the
devil with the solder." Yet, inefficient though the whitesmith was,
Watt could ill spare him, and we find him writing to Dr. Roebuck almost
in despair, saying, "My old white-iron man is dead!" feeling his loss
to be almost