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period, it is impossible to determine by means of it the precise time when the Egyptians began to adjust their vague and tropical years. We admit that the principle on which this adjustment was made applied only to a remote epoch, and afterwards ceased to be astronomically true; still as it was applicable to a large portion of that period-nearly thirty centuries the system referred to may have been introduced at an earlier or a later stage of it. On the whole, however, the coincidence of the four methods appears to afford very plausible ground for the opinion of the author, that Egypt was occupied by a people comparatively civilized about 2800 years before the birth of our Saviour. There can be no doubt that the foundations of social order were laid on the banks of the Nile before the most refined nations of Europe were inhabited, or had emerged from the state of barbarism; and hence there is nothing extravagant in the assertion that Egypt was an old country when it was first visited by the sages of Greece, and supplied to the islands of the Archipelago the elements of science and literature. But it is in vain that we now endeavour to ascertain the date at which the kingdom of the Pharoahs first assumed a regular form; when her wise men first calculated the return of the dogstar to the horizon with the rising sung and learned to speculate on the causes which produced the annual inundation of the Nile. Antiquity has invested such inquiries, with a cloud which we fruitlessly attempt to penetrate; and this difficulty is increased beyond all calculation by the circumstance that the authors from whose works we are anxious to derive information, are not consistent either with themselves or with one another. Joseph Scaliger lamented the discordance and imperfection of all chronological systems in the following pathetic terms, In multis judicium, in quibusdam diligentiam requiro; neque enim dum verum adepti sunt. Argumento fuerint omnium quotquot de his rebus tractarunt dissentiones; ut inter tot millia chronologorum vix inter duos de eadem re conveniat! Ab eorum lectione incertior atque indoctior sum quam dudum.
In these circumstances we are indebted to every one who attempts to throw a few rays of light on a subject so dark and perplexed; for, which reason we recommend the essays of Mr. Mure to the favourable attention of the chronological reader, who will find his labour rewarded by a careful and repeated study of their contents. IL
ART. VII.-Two Chapters, forming an Introduction to an Essay on Manufactures in the Encyclopædia Metropolitana. By Charles Babbage, Esq. M.A. F.R.S. London and Edinburgh, Lucasian Professor of Mathematics in the University of Cambridge. Chapter I. published in Part XXII.-Chapter II. in Part XXXIII. of the Encyclopædia Metropolitana.
RICH as are the pages of the Encyclopædia Metropolitana in varied treasures both of Science and Literature, there are perhaps few among its many invaluable Papers which will prove more generally attractive than this Introduction by Mr. Babbage. By a wise foresight on the part of the Proprietors of that great Work, this portion of it is likely also to obtain a circulation, we will not say commensurate with its merits, but among many persons who, from different causes, may be deterred from purchasing the entire Encyclopædia. The volume which it prefaces is intended to relate solely to Manufactures; and the body of it, containing an extended account of the application of Machinery to their fabric, is undertaken by gentlemen, the Messieurs Farey, whose names carry with them an ample voucher for the excellence of its execution. This single volume, when completed, (as indeed all the other volumes of the same Work,) may be purchased separately, and will form in itself a whole. So that at a comparatively trifling price, the Reader may obtain a synopsis of the numberless marvellous processes which have raised England to her extraordinary commercial elevation above all other Countries of all times-a synopsis written by those among our contemporaries who have shown, not only how well they can reason on mechanical theories, but who have splendidly distinguished themselves also by reducing those theories to practice.
We have thought it right to mention that Mr. Babbage's Introduction may be thus easily procured, because, in these days of cheap knowledge, no intrinsic value, however great, would be permitted to weigh against apparent exclusiveness. An author of our times must write for all, or he will not be read by any ;κοινὸς Ἑρμῇς και ἐς μέσον κατατίθει φέρων τὸν πλούτον—for Literature has become a real instead of a figurative Republic. One advantage, most assuredly, we have obtained over our forefathers by this wider diffusion of information among classes formerly doomed to ignorance: we mean in the more intelligible language by which Science is conveyed abroad. Philosophy no longer registers her decrees in esoteric symbols; she employs a plain Demotic character, for the interpretation of which we need not seek the Key of a Hierogrammatist. And no one, whom we recollect, has
more happily discarded that technical peculiarity which but a few years since rendered works of Science " caviare to the general," than Mr. Babbage in this preliminary Essay. He writes popularly in the best sense of the word; not by stooping to the throng, but, while he stands upright and maintains his fitting dignity, by placing himself within their reach.
In reviewing his Preface, we can do little more than condense into a narrow compass some of the extraordinary facts which he mentions, and allow him to display the merits of his style in others by extracting his own words.
The three chief advantages derived from Machinery and Manufactures may be represented by "the addition which they make to human power-the economy of human time-and the conversion of substances, apparently the most common and the most worthless, into valuable products;" and of these benefits some short, but striking illustrations, are offered by Mr. Babbage. The addition to human power may be perceived in an experiment which M. Redelet has noticed in his Work Sur l'Art de Bâtir.
"A block of squared stone was taken for the subject of experiment, weighing 1080 lbs.
1. Weight of stone.
2. In order to drag this stone along the floor of the quarry
3. The same stone dragged over a floor of planks required
5. After soaping the two surfaces of wood which slid over
6. The same stone was now placed upon rollers of three inches diameter, when it required to put it in motion along the floor of the quarry.
7. To drag it by these rollers over a wooden floor required 8. When the stone was mounted on a wooden platform, and the same rollers placed between that and a plank floor, it required
"From this experiment it results, that the force necessary to move a stone along the smoothed floor of its quarry is nearly two-thirds of its weight; to move it along a wooden floor, three-fifths; by wood upon wood, five-ninths; if the wooden surfaces are soaped, one sixth; rollers are used on the floor of the quarry, it requires one thirty-second part of the weight; if they roll over wood, one-fortieth; and if they roll between wood, one-fiftieth of its weight.-part xxii. p. 2.
The economy of time is exhibited in a recent improvement, made within twelve years, in the mounting of a glazier's diamond.
According to the old system, even after a diligently served ap prenticeship, many a journeyman was unable to acquire the nice art of finding the precise angle at which the diamond would cut, and afterwards of continuing to guide it at the proper inclination. All the time expended, and the glass destroyed in learning that knack, may now be saved by a very simple contrivance adjusted to the tool itself. Thirdly, the value of seemingly worthless materials is demonstrated in the metempsychosis undergone by defunct saucepans, kettles, and coal-skuttles.
"These have not yet completed their useful course; the less corroded parts are cut into strips, punched with small holes, and varnished with a coarse black varnish, for the use of the trunk-maker, who protects the edges and angles of his boxes with them; the remainder are conveyed to the manufacturing chemists in the out-skirts of the town, who employ them, in conjunction with pyroligneous acid, in making a black die for the use of calico printers."-part xxii. p. 4.
The cotton of Java is carried in junks to the coast of China, but the seed not being previously separated, only one quarter of the net weight is cotton; the cotton afterwards, as packed by the Chinese, occupies three times the space of an equal quantity shipped by Europeans for their own markets. Thus, from want of mechanical methods, the cost of the freight of a given quantity of cotton is twelve times greater, to a Chinese than it is to a European.
Boot-tag.laces, as is well known, consist of very thin, tinned plate-iron, and they used to be cut out of long strips of that material into pieces of such a breadth that, when bent round, they just inclosed the laces: Two pieces of steel have récently been fixed to the side of the shears, by which each piece of tin, as soon as it is cut, is bent into a semi-cylindrical form. The additional power required for this operation is almost insensible, and it is executed by the same motion of the arm which produces the cut. This work is usually performed by women and children, and with the improved tool more than three times the quantity is produced in a given time.
The improvements made of late years in the different processes of typography are among the most remarkable triumphs of mechanism.
"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 them 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 irregular, it was impossible to place on the type a uniform layer of ink, of exactly the quantity 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 to be produced only by mechanism.
"When printing presses moved by the power of steam were introduced, the action of these rollers was found well calculated to be performed by the machine, and a reservoir of ink was formed from which one roller regularly abstracted a small quantity at each impression. From three to five other rollers spread this portion uniformly over the 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 previously to its giving the impression on the paper. The following is an account of the results of an accurate experiment made at one of the largest printing establishments in the metropolis. 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.
"In order to show that this plan of inking puts the proper quantity of ink upon the type, we must prove first that it 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 much. This latter point is satisfactorily established by a reference to the frequency of change of what is called the set-off sheet' in the old method. 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 on 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, and acquires from them more or less of the ink, according to their dryness or the quantity upon them. It was usual in the former process, after about one hundred impressions, to change the set-off sheet, which in that time became too much soiled for further use. In the new method of printing by machinery no set-off 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 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
NO. XXIII.—JULY, 1832.