hich he had been working entirely after the methods described
in books; but, feeling the results still unsatisfactory, he determined
to borrow no more from the books, but to work out a system of his own,
which should ensure results similar to those produced at the
blast-furnace. This he eventually succeeded in effecting by numerous
experiments performed in the night; as his time was fully occupied by
his office-duties during the day. At length these patient experiments
bore their due fruits. David Mushet became the most skilled assayer at
the works; and when a difficulty occurred in smelting a quantity of new
ironstone which had been contracted for, the manager himself resorted
to the bookkeeper for advice and information; and the skill and
experience which he had gathered during his nightly labours, enabled
him readily and satisfactorily to solve the difficulty and suggest a
suitable remedy. His reward for this achievement was the permission,
which was immediately granted him by the manager, to make use of his
own assay-furnace, in which he thenceforward continued his
investigations, at the same time that he instructed the manager's son
in the art of assaying. This additional experience proved of great
benefit to him; and he continued to prosecute his inquiries with much
zeal, sometimes devoting entire nights to experiments in assaying,
roasting and cementing iron-ores and ironstone, decarbonating cast-iron
for steel and bar-iron, and various like operations. His general
practice, however, at that time was, to retire between two and three
o'clock in the morning, leaving directions with the engine-man to call
him at half-past five, so as to be present in the office at six. But
these praiseworthy experiments were brought to a sudden end, as thus
described by himself:--

"In the midst of my career of investigation," says he,[6] "and without
a cause being assigned, I was stopped short. My furnaces, at the order
of the manager, were pulled in pieces, and an edict was passed that
they should never be erected again. Thus terminated my researches at
the Clyde Iron Works. It happened at a time when I was interested--and
I had been two years previously occupied--in an attempt to convert
cast-iron into steel, without fusion, by a process of cementation,
which had for its object the dispersion or absorption of the
superfluous carbon contained in the cast-iron,--an object which at that
time appeared to me of so great impo