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parts of it would be dark in proportion to their

inclination. Other species of engraving might be conceived by

substituting, instead of the imaginary plane, an imaginary sphere

or other solid, intersecting the figure in the medal.

 

158. Lace made by caterpillars. A most extraordinary species

of manufacture, which is in a slight degree connected with

copying, has been contrived by an officer of engineers residing

at Munich. It consists of lace, and veils, with open patterns in

them, made entirely by caterpillars. The following is the mode of

proceeding adopted: he makes a paste of the leaves of the plant,

which is the usual food of the species of caterpillar(4*) he

employs, and spreads it thinly over a stone, or other flat

substance. He then, with a camel-hair pencil dipped in olive oil,

draws upon the coating of paste the pattern he wishes the insects

to leave open. This stone is then placed in an inclined position,

and a number of the caterpillars are placed at the bottom. A

peculiar species is chosen, which spins a strong web; and the

animals commencing at the bottom, eat and spin their way up to

the top, carefully avoiding every part touched by the oil, but

devouring all the rest of the paste. The extreme lightness of

these veils, combined with some strength, is truly surprising.

One of them, measuring twenty-six and a half inches by seventeen

inches, weighed only 1.51 grains; a degree of lightness which

will appear more strongly by contrast with other fabrics. One

square yard of the substance of which these veils are made weighs

4 1/3 grains, whilst one square yard of silk gauze weighs 137

grains, and one square yard of the finest patent net weighs 262

1/2 grains. The ladiesā€™ coloured muslin dresses, mentioned in the

table subjoined, cost ten shillings per dress, and each weigh six

ounces; the cotton from which they are made weighing nearly six

and two-ninth ounces avoirdupois weight.

 

Weight of one square yard of each of the following articles(5*)

 

Weight of

Weight cotton used

Value finished of in waking

per yard one square one square

Description of goods measure yard yard

 

s. d. Troy grains Troy grains

 

Caterpillar veils ā€” 4 1/3 ā€”

Silk gauze 3-4 wide 1 0 137 ā€”

Finest patent net ā€” 262 1/2 ā€”

Fine cambric muslin ā€” 551 ā€”

6-4ths jaconet muslin 2 0 613 670

Ladiesā€™ coloured muslin dresses 3 0 788 875

6-4ths cambric 1 2 972 1069

9-8ths calico 0 9 988 1085

1/2-yard nankeen 0 8 2240 2432

 

159. This enumeration, which is far from complete, of the

arts in which copying is the foundation, may be terminated with

an example which has long been under the eye of the reader;

although few, perhaps, are aware of the number of repeated

copyings of which these very pages are the subject.

 

1. They are copies, by printing, from stereotype plates.

 

2. These stereotype plates are copied, by the art of casting,

from moulds formed of plaster of Paris.

 

3. These moulds are themselves copied by casting the plaster

in a liquid state upon the moveable types set up by the

compositor.

 

[It is here that the union of the intellectual and the

mechanical departments takes place. The mysteries, however, of an

authorā€™s copying, form no part of our enquiry, although it may be

fairly remarked, that, in numerous instances, the mental far

eclipses the mechanical copyist.]

 

4. These moveable types, the obedient messengers of the most

opposite thoughts, the most conflicting theories, are themselves

copies by casting from moulds of copper called matrices.

 

5. The lower part of those matrices, bearing the impressions

of the letters or characters, are copies, by punching, from steel

punches on which the same characters exist in relief.

 

6. These steel punches are not themselves entirely exempted

from the great principle of art. Many of the cavities which exist

in them, such as those in the middle of the punches for the

letters a, b, d, e, g, etc., are produced from other steel

punches in which these parts are in relief.

 

We have thus traced through six successive stages of copying

the mechanical art of printing from stereotype plates: the

principle of copying contributing in this, as in every other

department of manufacture, to the uniformity and the cheapness of

the work produced.

 

NOTES:

 

1. The late Mr Lowry.

 

2. I posses a lithographic reprint of a page of a table, which

appears, from the from of the type, to have been several years

old.

 

3. The construction of the engraving becomes evident on examining

it with a lens of sufficient power to show the continuity of the

lines.

 

4. The Phalaena pardilla, which feeds on the Prunus padus.

 

5. Some of these weights and measures are calculated from a

statement in the Report of the Committee of the House of Commons

on Printed Cotton Goods; and the widths of the pieces there given

are presumed to be the real widths, not those by which they are

called in the retail shops.

Chapter 12

On the Method of Observing Manufacturies

 

160. Having now reviewed the mechanical principles which

regulate the successful application of mechanical science to

great establishments for the production of manufactured goods, it

remains for us to suggest a few enquiries, and to offer a few

observations, to those whom an enlightened curiosity may lead to

examine the factories of this or of other countries.

 

The remarkā€”that it is important to commit to writing all

information as soon as possible after it is received, especially

when numbers are concernedā€”applies to almost all enquiries. It

is frequently impossible to do this at the time of visiting an

establishment, although not the slightest jealousy may exist; the

mere act of writing information as it is communicated orally, is

a great interruption to the examination of machinery. In such

cases, therefore, it is advisable to have prepared beforehand the

questions to be asked, and to leave blanks for the answers, which

may be quickly inserted, as, in a multitude of cases, they are

merely numbers. Those who have not tried this plan will be

surprised at the quantity of information which may, through its

means, be acquired, even by a short examination. Each manufacture

requires its own list of questions, which will be better drawn up

after the first visit. The following outline, which is very

generally applicable, may suffice for an illustration; and to

save time, it may be convenient to have it printed; and to bind

up, in the form of a pocket-book, a hundred copies of the

skeleton forms for processes, with about twenty of the general

enquiries.

 

GENERAL ENQUIRIES

 

Outlines of a description of any of the mechanical arts ought to

contain information on the following points

 

Brief sketch of its history, particularly the date of its

invention, and of its introduction into England.

 

Short reference to the previous states through which the

material employed has passed: the places whence it is procured:

the price of a given quantity.

 

[The various processes must now be described successively

according to the plan which will be given in (161); after which

the following information should be given.]

 

Are various kinds of the same article made in one establishment,

or at different ones, and are there differences in the processes?

 

To what defects are the goods liable?

 

What substitutes or adulterations are used?

 

What waste is allowed by the master?

 

What tests are there of the goodness of the manufactured

articles?

 

The weight of a given quantity, or number, and a comparison

with that of the raw material?

 

The wholesale price at the manufactory? (L s. d.) per ( )

 

The usual retail price? (L s. d.)

 

Who provide tools? Master, or men? Who repair tools? Master,

or men?

 

What is the expense of the machinery?

 

What is the annual wear and tear, and what its duration?

 

Is there any particular trade for making it? Where?

 

Is it made and repaired at the manufactory?

 

In any manufactory visited, state the number ( ) of

processes; and of the persons employed in each process; and the

quantity of manufactured produce.

 

What quantity is made annually in Great Britain?

 

Is the capital invested in manufactories large or small?

 

Mention the principal seats of this manufacture in England;

and if it flourishes abroad, the places where it is established.

 

The duty, excise. or bounty, if any, should be stated, and

any alterations in past years; and also the amount exported or

imported for a series of years.

 

Whether the same article, but of superior, equal, or inferior

make, is imported?

 

Does the manufacturer export, or sell, to a middleman, who

supplies the merchant?

 

To what countries is it chiefly sent? and in what goods are

the returns made?

 

161. Each process requires a separate skeleton, and the

following outline will be sufficient for many different

manufactories:

 

Process ( ) Manufacture ( )

Place ( ) Name ( )

date 183

 

The mode of executing it, with sketches of the tools or

machine if necessary.

 

The number of persons necessary to attend the machine. Are

the operatives men. ( ) women, ( ) or children? ( ) If mixed,

what are the proportions?

 

What is the pay of each? (s. d.) (s. d. ) (s. d.) per ( )

 

What number ( ) of hours do they work per day?

 

Is it usual, or necessary, to work night and day without

stopping? Is the labour performed by pieceā€”or by day-work?

 

Who provide tools? Master, or men? Who repair tools? Master,

or men? What degree of skill is required, and how many yearsā€™ ( )

apprenticeship?

 

The number of times ( ) the operation is repeated per day or

per hour?

 

The number of failures ( ) in a thousand?

 

Whether the workmen or the master loses by the broken or

damaged articles?

 

What is done with them?

 

If the same process is repeated several times, state the

diminution or increase of measure, and the loss, if any, at each

repetition.

 

162. In this skeleton, the answers to the questions are in

some cases printed, as ā€œWho repair the tools?ā€”Masters, Menā€; in

order that the proper answer may be underlined with a pencil. In

filling up the answers which require numbers, some care should be

taken: for instance, if the observer stands with his watch in his

hand before a person heading a pin, the workman will almost

certainly increase his speed, and the estimate will be too large.

A much better average will result from enquiring what quantity is

considered a fair dayā€™s work. When this cannot be ascertained,

the number of operations performed in a given time may frequently

be counted when the workman is quite unconscious that any person

is observing him. Thus the sound made by the motion of a loom may

enable the observer to count the number of strokes per minute,

even though he is outside the building in which it is contained.

M. Coulomb, who had great experience in making such observations,

cautions those who may repeat his experiments against being

deceived by such circumstances: ā€˜Je prieā€™ (says he) ā€˜ceux qui

voudront les repeter, sā€™ils nā€™ont pas le temps de mesurer les

resultats apres plusiers jours dā€™un travail continu, dā€™observer

les ouvriers a differentes reprises dans la journee, sans quā€™ils

sachent quā€™ils sont observes. Lā€™on ne peut trop avertir combien

lā€™on risque de se tromper en calculant, soit la vitesse, soit le

temps effectif du travail, dā€™apres une observation de quelques

minutes.ā€™ Memoires de lā€™Institut. vol. II, p. 247.

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