On the Economy of Machinery and Manufactures, Charles Babbage [classic romance novels .TXT] 📗
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sufficient merely to indicate a few of their sources. They
frequently arise from having neglected to take into consideration
that metals are not perfectly rigid but elastic. A steel cylinder
of small diameter must not be regarded as an inflexible rod; but
in order to ensure its perfect action as an axis, it must be
supported at proper intervals.
Again, the strength and stiffness of the framing which
supports the mechanism must be carefully attended to. It should
always be recollected, that the addition of superfluous matter to
the immovable parts of a machine produces no additional momentum,
and therefore is not accompanied with the same evil that arises
when the moving parts are increased in weight. The stiffness of
the framing in a machine produces an important advantage. If the
bearings of the axis (those places at which they are supported)
are once placed in a straight line, they will remain so, if the
framing be immovable; whereas if the framework changes its form,
though ever so slightly, considerable friction is immediately
produced. This effect is so well understood in the districts
where spinning factories are numerous, that, in estimating the
expense of working a new factory, it is allowed that five per
cent on the power of the steamengine will be saved if the
building is fireproof: for the greater strength and rigidity of a
fireproof building prevents the movement of the long shafts or
axes which drive the machinery, from being impeded by the
friction that would arise from the slightest deviation in any of
the bearings.
323. In conducting experiments upon machinery, it is quite a
mistake to suppose that any imperfect mechanical work is good
enough for such a purpose. If the experiment is worth making, it
ought to be tried with all the advantages of which the state of
mechanical art admits; for an imperfect trial may cause an idea
to be given up, which better workmanship might have proved to be
practicable. On the other hand, when once the efficiency of a
contrivance has been established, with good workmanship it will
be easy afterwards to ascertain the degree of perfection which
will suffice for its due action.
324. It is partly owing to the imperfection of the original
trials, and partly to the gradual improvements in the art of
making machinery, that many inventions which have been tried, and
given up in one state of art, have at another period been
eminently successful. The idea of printing by means of moveable
types had probably suggested itself to the imagination of many
persons conversant with impressions taken either from blocks or
seals. We find amongst the instruments discovered in the remains
of Pompeii and Herculaneum, stamps for words formed out of one
piece of metal, and including several letters. The idea of
separating these letters, and of recombining them into other
words, for the purpose of stamping a book, could scarcely have
failed to occur to many: but it would almost certainly have been
rejected by those best acquainted with the mechanical arts of
that time; for the workmen of those days must have instantly
perceived the impossibility of producing many thousand pieces of
wood or metal, fitting so perfectly and ranging so uniformly, as
the types or blocks of wood now used in the art of printing.
The principle of the press which bears the name of Bramah,
was known about a century and a half before the machine, to which
it gave rise, existed; but the imperfect state of mechanical art
in the time of the discoverer, would have effectually deterred
him, if the application of it had occurred to his mind, from
attempting to employ it in practice as an instrument for exerting
force.
These considerations prove the propriety of repeating, at the
termination of intervals during which the art of making machinery
has received any great improvement, the trails of methods which,
although founded upon just principles, had previously failed.
325. When the drawings of a machine have been properly made,
and the parts have been well executed, and even when the work it
produces possesses all the qualities which were anticipated,
still the invention may fail; that is, it may fail of being
brought into general practice. This will most frequently arise
from the circumstance of its producing its work at a greater
expense than that at which it can be made by other methods.
326. Whenever the new, or improved machine, is intended to
become the basis of a manufacture, it is essentially requisite
that the whole expense attending its operations should be fully
considered before its construction is undertaken. It is almost
always very difficult to make this estimate of the expense: the
more complicated the mechanism, the less easy is the task; and in
cases of great complexity and extent of machinery it is almost
impossible. It has been estimated roughly, that the first
individual of any newly invented machine, will cost about five
times as much as the construction of the second, an estimate
which is, perhaps, sufficiently near the truth. If the second
machine is to be precisely like the first, the same drawings, and
the same patterns will answer for it; but if, as usually happens,
some improvements have been suggested by the experience of the
first, these must be more or less altered. When, however, two or
three machines have been completed, and many more are wanted,
they can usually be produced at much less than one-fifth of the
expense of the original invention.
327. The arts of contriving, of drawing, and of executing, do
not usually reside in their greatest perfection in one
individual; and in this, as in other arts, the division of labour
must be applied. The best advice which can be offered to a
projector of any mechanical invention, is to employ a respectable
draughtsman; who, if he has had a large experience in his
profession, will assist in finding out whether the contrivance is
new, and can then make working drawings of it. The first step,
however, the ascertaining whether the contrivance has the merit
of novelty, is most important; for it is a maxim equally just in
all the arts, and in every science, that the man who aspires to
fortune or to fame by new discoveries, must be content to examine
with care the knowledge of his contemporaries, or to exhaust his
efforts in inventing again, what he will most probably find has
been better executed before.
328. This, nevertheless, is a subject upon which even
ingenious men are often singularly negligent. There is, perhaps,
no trade or profession existing in which there is so much
quackery, so much ignorance of the scientific principles, and of
the history of their own art, with respect to its resources and
extent, as are to be met with amongst mechanical projectors. The
self-constituted engineer, dazzled with the beauty of some,
perhaps, really original contrivance, assumes his new profession
with as little suspicion that previous instruction, that thought
and painful labour, are necessary to its successful exercise, as
does the statesman or the senator. Much of this false confidence
arises from the improper estimate which is entertained of the
difficulty of invention in mechanics. It is, therefore, of great
importance to the individuals and to the families of those who
are too often led away from more suitable pursuits, the dupes of
their own ingenuity and of the popular voice, to convince both
them and the public that the power of making new mechanical
combinations is a possession common to a multitude of minds, and
that the talents which it requires are by no means of the highest
order. It is still more important that they should be impressed
with the conviction that the great merit, and the great success
of those who have attained to eminence in such matters, was
almost entirely due to the unremitted perseverance with which
they concentrated upon their successful inventions the skill and
knowledge which years of study had matured.
Proper Circumstances for the Application of Machinery
329. The first object of machinery, the chief cause of its
extensive utility, is the perfection and the cheap production of
the articles which it is intended to make. Whenever it is
required to produce a great multitude of things, all of exactly
the same kind, the proper time has arrived for the construction
of tools or machines by which they may be manufactured. If only a
few pairs of cotton stockings should be required, it would be an
absurd waste of time, and of capital, to construct a
stocking-frame to weave them, when, for a few pence, four steel
wires can be procured by which they may be knit. If, on the other
hand, many thousand pairs were wanted, the time employed, and the
expense incurred in constructing a stocking-frame, would be more
than repaid by the saving of time in making that large number of
stockings. The same principle is applicable to the copying of
letters: if three or four copies only are required, the pen and
the human hand furnish the cheapest means of obtaining them; if
hundreds are called for, lithography may be brought to our
assistance; but if hundreds of thousands are wanted, the
machinery of a printing establishment supplies the most
economical method of accomplishing the object.
330. There are, however, many cases in which machines or
tools must be made, in which economical production is not the
most important object. Whenever it is required to produce a few
articles parts of machinery, for instance, which must be executed
with the most rigid accuracy or be perfectly alike—it is nearly
impossible to fulfil this condition, even with the aid of the
most skilful hands: and it becomes necessary to make tools
expressly for the purpose, although those tools should, as
frequently happens, cost more in constructing than the things
they are destined to make.
331. Another instance of the just application of machinery,
even at an increased expense, arises where the shortness of time
in which the article is produced, has an important influence on
its value. In the publication of our daily newspapers, it
frequently happens that the debates in the Houses of Parliament
are carried on to three and four o’clock in the morning, that is.
to within a very few hours of the time for the publication of the
paper. The speeches must be taken down by reporters, conveyed by
them to the establishment of the newspaper, perhaps at the
distance of one or two miles, transcribed by them in the office,
set up by the compositor, the press corrected, and the paper be
printed off and distributed, before the public can read them.
Some of these journals have a circulation of from five to ten
thousand daily. Supposing four thousand to be wanted, and that
they could be printed only at the rate of five hundred per hour
upon one side of the paper, (which was the greatest number two
journeymen and a boy could take off by the old hand presses),
sixteen hours would be required for printing the complete
edition; and the news conveyed to the purchasers of the latest
portion of the impression, would be out of date before they could
receive it. To obviate this difficulty, it was often necessary to
set up the paper in duplicate, and sometimes, when late, in
triplicate: but the improvements in the printing machines have
been so great, that four thousand copies are now printed on one
side in an hour.
332. The establishment of ‘The Times’ newspaper is an
example, on a large scale, of a manufactory in which the division
of labour, both mental and bodily, is admirably illustrated, and
in which also the effect of domestic economy is well exemplified.
It is scarcely imagined by the thousands
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