When an industry has thus chosen a locality for itself, it is likely to stay there long: so
great are the advantages
which people following the same skilled trade get from near neighbourhood to one another. The mysteries of the trade become no
mysteries; but are as
it were in the air, and children learn many of them unconsciously. Good work is
rightly appreciated,
inventions and improvements in machinery, in processes and the general organization of the business have their merits
promptly discussed: if one
man starts a new idea, it is taken up by others and combined with suggestions of
their own; and thus it
becomes the source of further new ideas. And presently subsidiary trades grow up
in the neighbourhood,
supplying it with implements and materials, organizing its traffic, and in many ways conducing to the economy of its
material.
— Marshall, Principles of Economics, IV.x.3.