227.  As the clear apprehension of this principle, upon which a great part of the economy arising from the division of labour depends, is of considerable importance, it may be desirable to point out its precise and numerical application in some specific manufacture.  The art of making needles is, perhaps, that which I should have selected for this illustration, as comprehending a very large number of processes remarkably different in their nature; but the less difficult art of pinmaking, has some claim to attention, from its having been used by Adam Smith; and I am confirmed in the choice of it, by the circumstance of our possessing a very accurate and minute description of that art, as practised in France above half a century ago.

228.  Pin-making.  In the manufacture of pins in England the following processes are employed: 

1.  Wire-drawing. (a) The brass wire used for making pins is purchased by the manufacturer in coils of about twenty-two inches in diameter, each weighing about thirty-six pounds. (b) The coils are wound off into smaller ones of about six inches in diameter, and between one and two pounds’ weight. (c) The diameter of this wire is now reduced, by drawing it repeatedly through holes in steel plates, until it becomes of the size required for the sort of pins intended to be made.  During this process the wire is hardened, and to prevent its breaking, it must be annealed two or three times, according to the diminution of diameter required. (d) The coils are then soaked in sulphuric acid, largely diluted with water, in order to clean them, and are then beaten on stone, for the purpose of removing any oxidated coating which may adhere to them.  These operations are usually performed by men, who draw and clean from thirty to thirty-six pounds of wire a day.  They are paid at the rate of five farthings per pound, and generally earn about 3s. 6d. per day.

M. Perronnet made some experiments on the extension the wire undergoes in passing through each hole:  he took a piece of thick Swedish brass wire, and found

Feet Inches Its length to be before drawing 3 8 After passing the first hole 5 5 second hole 7 2 third hole 7 8

 It was now annealed, and the length became

After passing the fourth hole 10 8 fifth hole 13 1 sixth hole 16 8 And finally, after passing through six other holes 144 0

The holes through which the wire was drawn were not, in this experiment, of regularly decreasing diameter:  it is extremely difficult to make such holes, and still more to preserve them in their original dimensions.