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being left plain. In the circular end q (shown more distinctly in the end view, fig. 14), is cut a dove-tailed groove, in which the jaws r r slide. Each of these jaws is made of steel, and in the form of half a truncated cone, with a sliding dove-tail at the bottom of each, which enters the dove-tailed groove made across the circular end of the chuck. Figs. 17 and 18 are front and side views of one of the jaws. The cap t has a hollow screw cut within it, which fits the external screw o o, fig. 16; and likewise a plain cylindrical part, which exactly fits the cylindrical part p of the body of the chuck, and greatly assists in steadying the cap behind*; and at the end of the cap is screwed or riveted a thick steel plate u u, figs. 13 and 14, the centre of which is pierced with a conical hole, just wide enough to allow the jaws to project through it about half their length.

In order to use this chuck, the cap is taken off, and the two jaws are slid from the centre, to admit the wire between them; the jaws are then closed upon the wire, and the cap is screwed on; during this latter operation, whatever eccentricity might at first have existed in the position of the jaws, is corrected by the pressure of the conical hole in the steel plate, upon the conical sides of the jaws; so that the mere act of screwing on the cap, necessarily brings the cylinder of wire placed between the jaws into the true centre of the chuck.

This chuck is also well adapted for holding wire to be cut and turned into small screws; as well as for receiving and actuating drills of all sorts and sizes in the lathe; and thus entirely saving the time which is generally lost in adjusting them truly.

To the workman desirous of making this chuck, the following directions will be of use :-Take a piece of brass, or

* In a similar manner to the chucks of Mr. Saxton's American lathe, described in vol. V. page 105; and indeed Mr. Mordan, on seeing it, stated, that he had also employed a similar means. We think the whole chuck would be improved, by adopting that manner of fitting it upon the lathe-mandrel. EDITOR.

gun metal, one and three-quarter inches long, and the same in diameter; turn a hollow screw in one end of it, and fix it firmly on the mandrel of the lathe, so that there shall not be the least degree of shake (see the preceding note, EDIT.); then, cut an external screw on the other end of it, half an inch long, also leaving a plain cylindrical surface, of the same length, between the screw and the raised ring in which the lever-hole is made. In and across the external flat end of this piece of brass, cut a dove-tailed groove; then take a flat piece of steel, having a cylindrical stud, five-eighths of an inch thick, and the same in height, projecting from the middle of its upper face; shape and adjust this piece of steel so that it shall fit the dove-tailed groove accurately, and yet slide easily in it; then turn the cylindrical stud into the figure of a truncated cone, fiveeighths of an inch wide at bottom, and one quarter of an inch at top. Next, take a collar of brass, or gun-metal, and cut in it a hollow screw, to fit the external one formed upon the first piece of brass; also let into the outer end of this collar, a disc of sheet steel, one and three-quarter inch in diameter, and one-eighth of an inch thick, and fix it in its place by screws or rivets; then pierce a hole through the centre of it, of a conical form, so as to fit the conical upper half of the steel stud. Next, screw the cap tight on the stud, and bore a hole truly in the axis of the chuck, through the stud, and continue it, till it reaches the screw of the lathe mandrel; then take out the steel slider, and enlarge the hole drilled in the axis of the chuck, until it will receive easily the thickest wire that is wanted to be turned. Lastly, divide the steel slider, by a transverse cut, into two jaws, and angle them within, so that they shall hold firmly, whatever work may be put between them.

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LX. —On the advantages attending the Division of Labour, and the employment of Machinery, By the celebrated Dr. A SMITH*.

"THE annual labour of every nation is the fund which originally supplies it with all the necessaries and conveniences of life which it annually consumes, and which consist either in the immediate produce of that labour, or in what is purchased with that labour from other nations.

"According, therefore, as this produce, or what is purchased with it, bears a greater or smaller proportion to the number of those who are to consume it, the nation will be better or worse supplied with all the necessaries for which it has occasion.

"But this proportion must, in every nation, be regulated by two different circumstances; first, by the skill, dexterity, and judgment with which its labours are generally applied ; and, secondly, by the proportion between the number of those who are employed in useful labour, and that of those who are not so employed. Whatever be the soil, climate, or extent of territory, of any particular nation, the abundance or scantiness of its annual supply must, in that particular situation, depend upon these two circumstances.

"The abundance or scantiness of this supply too seems to depend more upon the former of those two circumstances, than upon the latter. Among the savage nations of hunters and fishers, every individual who is able to work, is more or less employed in useful labour, and endeavours to provide, as well as he can, the necessaries and conveniencies of life for himself, or such of his tribe as are either too old or too young, or too infirm to go a hunting or fishing. Such nations, however, are so miserably poor, that from mere want, they are frequently reduced, or at least think themselves reduced, to the necessity sometimes of directly destroying, and sometimes of abandoning, their infants, the old people, and those afflicted with lingering From his "Wealth of Nations.”

diseases, to perish with hunger, or to be devoured by wild beasts. Among civilized and thriving nations, on the contrary, though a great number of people do not labour at all, many of whom consume the produce of ten times, frequently of a hundred times, more labour than the greater part of those who work; yet the produce of the whole labour of the society is so great, that all are often abundantly supplied; and a workman even of the lowest and poorest order, if he is frugal and industrious, may enjoy a greater share of the necessaries and conveniences of life than it is possible for any savage to acquire.

"The causes of this improvement in the productive powers of labour, and the order according to which it is produced, and is naturally distributed among the different ranks and conditions of men in the society, make the subject of this inquiry.

"The greatest improvement in the productive powers of labour, and the greater part of the skill, dexterity, and judgment with which it is any where directed or applied, seem to have been the effects of the division of labour.

"The effects of the division of labour, in the general business of society, will be more easily understood, by considering how it operates in some particular manufactures. It is commonly supposed to be carried farthest in some very trifling ones; not perhaps that it really is carried farther in them than in others of more importance; but in those trifling manufactures which are destined to supply the small wants of but a small number of people, the whole number of workmen must necessarily be small; and those employed in every branch of the work, can often be collected into the same workshop, and be placed at once under the view of the spectator. In those great manufactures, on the contrary, which are destined to supply the wants of the great body of the people, every different branch of the work employs so great a number of workmen, that it is impossible to collect them all into the shop. We can seldom see more, at one time, than those employed in one single

branch. Though in such manufactures, therefore, the work may be really divided into a much greater number of parts than in those of a trifling nature, the division is not near so obvious, and has accordingly been much less observed.

"To take an example, therefore, from a very trifling manufacture, but one in which the division of labour has been very often taken notice of, the trade of the pin-maker; a workman not educated to this business (which the division of labour has rendered a distinct trade), nor acquainted with the use of the machinery employed in it (to the invention of which the same division of labour has probably given occasion), could scarce, perhaps, with his utmost industry, make one pin in a day, and certainly could not make twenty. But in the way in which this business is now carried on, not only the whole work is a peculiar trade, but it is divided into a number of branches, of which the greater part are likewise peculiar trades. One man draws the wire, another straightens it, a third cuts it, a fourth points it, a fifth grinds it at the top for receiving the head; to make the head requires two or three distinct operations, to put it on is a peculiar business, to whiten the pins is another; it is even a trade by itself to put them into the paper; and the important business of making a pin, is, in this manner, divided into about eighteen distinct operations, which, in some manufactories, are all performed by distinct hands, though in others the same man will sometimes perform two or three of them. I have seen a small manufactory of this kind, where ten men only were employed, and where some of them consequently performed two or three distinct operations. But though they were very poor, and therefore indifferently accommodated with the necessary machinery, they could, when they exerted themselves, make among them about twelve pounds of pins in a day; there are in a pound upwards of four thousand pins of a middling size; those ten persons, therefore, could make among them upwards of forty-eight thousand pins in a day; each person, therefore, making a tenth part of

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