CHAPTER 9.

Economy of the Materials Employed

77. The precision with which all operations by machinery are
executed, and the exact similarity of the articles thus made,
produce a degree of economy in the consumption of the raw
material which is, in some cases, of great importance. The
earliest mode of cutting the trunk of a tree into planks, was by
the use of the hatchet or the adze. It might, perhaps, be first
split into three or four portions, and then each portion was
reduced to a uniform surface by those instruments. With such
means the quantity of plank produced would probably not equal the
quantity of the raw material wasted by the process: and, if the
planks were thin, would certainly fall far short of it. An
improved tool, completely reverses the case: in converting a tree
into thick planks, the saw causes a waste of a very small
fractional part; and even in reducing it to planks of only an
inch in thickness, does not waste more than an eighth part of the
raw material. When the thickness of the plank is still further
reduced, as is the case in cutting wood for veneering, the
quantity of material destroyed again begins to bear a
considerable proportion to that which is used; and hence circular
saws, having a very thin blade, have been employed for such
purposes. In order to economize still further the more valuable
woods, Mr Brunel contrived a machine which, by a system of
blades, cut off the veneer in a continuous shaving, thus
rendering the whole of the piece of timber available.

78. The rapid improvements which have taken place in the
printing press during the last twenty years, afford another
instance of saving in the materials consumed, which has been well
ascertained by measurement, and is interesting from its
connection with literature. In the old method of inking type, by
large hemispherical balls stuffed and covered with leather, the
printer, after taking a small portion of ink from the ink-block,
was continually rolling the balls in various directions against
each other, in order that a thin layer of ink might be uniformly
spread over their surface. This he again transferred to the type
by a kind of rolling action. In such a process, even admitting
considerable skill in the operator, it could not fail to happen
that a large quantity of ink should get near the edges of the
balls, which, not being transferred to the type, became hard and
useless, and was taken off in the form of a thick black crust.
Another inconvenience also arose--the quantity of ink spread on
the block not being regulated by measure, and the number and
direction of the transits of the inking-balls over each other
depending on the will of the operator, and being consequently
irregular, it was impossible to place on the type a uniform layer
of ink, of the quantity exactly sufficient for the impression.
The introduction of cylindrical rollers of an elastic substance,
formed by the mixture of glue and treacle, superseded the
inking-balls, and produced considerable saving in the consumption
of ink: but the most perfect economy was only to be produced by
mechanism. When printing-presses, moved by the power of steam,
were introduced, the action of these rollers was found to be well
adapted to their performance; and a reservoir of ink was formed,
from which a roller regularly abstracted a small quantity at each
impression. From three to five other rollers spread this portion
uniformly over a slab (by most ingenious contrivances varied in
almost each kind of press), and another travelling roller, having
fed itself on the slab, passed and repassed over the type just
before it gave the impression to the paper.

In order to shew that this plan of inking puts the proper
quantity of ink upon the type, we must prove, first--that the
quantity is not too little: this would soon have been discovered
from the complaints of the public and the booksellers; and,
secondly that it is not too great. This latter point was
satisfactorily established by an experiment. A few hours after
one side of a sheet of paper has been printed upon, the ink is
sufficiently dry to allow it to receive the impression upon the
other; and, as considerable pressure is made use of, the tympan
on which the side first printed is laid, is guarded from soiling
it by a sheet of paper called the set-off sheet. This paper
receives, in succession, every sheet of the work to be printed,
acquiring from them more or less of the ink, according to their
dryness, or the quantity upon them. It was necessary in the
former process, after about one hundred impressions, to change
this set-off sheet, which then became too much soiled for further
use. In the new method of printing by machinery, no such sheet is
used, but a blanket is employed as its substitute; this does not
require changing above once in five thousand impressions, and
instances have occurred of its remaining sufficiently clean for
twenty thousand. Here, then, is a proof that the quantity of
superfluous ink put upon the paper in machine-printing is so
small, that, if multiplied by five thousand, and in some
instances even by twenty thousand, it is only sufficient to
render useless a single piece of clean cloth.(1*) The following
were the results of an accurate experiment upon the effect of the
process just described, made at one of the largest printing
establishments in the metropolis.(2*) Two hundred reams of paper
were printed off, the old method of inking with balls being
employed; two hundred reams of the same paper, and for the same
book, were then printed off in the presses which inked their own
type. The consumption of ink by the machine was to that by the
balls as four to nine, or rather less than one-half.

NOTES:

1. In the very best kind of printing, it is necessary, in the old
method, to change the set-off sheet once in twelve times. In
printing the same kind of work by machinery, the blanket is
changed once in 2000.

2. This experiment was made at the establishment of Mr Clowes, in
Stamford Street.