Excise vigilance, the trader occasionally defrauded; but owing to the
great heat of the arch, and the usual Excise securities, the revenue was,
on the whole well secured at the lears. Had the lears or kiln been the
only departments of the works under Excise survey, the manufacturer would
not have been so much inconvenienced. The surveillance of the pots was
his chief annoyance, since it required endless trouble, and subjected
the manufacturer to danger of Exchequer prosecutions. To throw into
the pots ever so small a piece of metal, during the working, incurred
a penalty of fifty pounds for every offence. Neither plate Glass nor
bottle Glass manufacturers were subject to the surveillance of the
pots: this made it exclusively injurious to the flint Glass makers,
and was almost a prohibition of alteration of tint, or experiments,
and consequent improvements.
It is a matter of astonishment how Flint
Glass works existed at all under such a concentration of commercial
and manufacturing hindrances as were imposed by the Excise regulations;
happily, the incubus exists only in reminiscence.
To return to a few of the curiosities
of Annealing. Coke, as has been stated, is the best fuel for this
process: it is the most steady and uniform in its calorific powers.
Oven-burnt coke is stronger and much more lasting than gas coke; another
advantage is, that it is the most free from carbonaceous fumes, or smoke.
Fluid Glass need not, therefore, be tinted in excess, only a minimum
quantity of manganese being in such case necessary. If coal be used,
the smoke, acting by its carbon upon the Glass, will render colourless