This is well exemplified by industrial and commercial development. With regard to manufacturing, there is specialization, not only in the handiwork, but also in the locality of production. Thus, in Great Britain, where this development has most fully matured itself, 'the calico manufacture locates itself in this county, the woollen-cloth manufacture in that; silks are produced here, lace there, stockings in one place, shoes in another; pottery, hardware, cutlery, come to have their special towns; and ultimately, every locality becomes more or less distinguished from the rest by the leading occupation carried on in it. Nay, more, this subdivision of functions shows itself, not only among the different parts of the same nation, but among different nations.' (Westminster Review.) Some of our economists object to this process, and would bring all kinds of productive labor into the same district; but a law higher than their theories brings artisans of the same kind into the neighborhood of each other;--it is the cooeperative action of the principles of differentiation and unitization. The effect of this process is to make one locality dependent on another locality. Once, as we have seen, the family was adequate to its own needs; now, we perceive the industrial producers of one district have become dependent on each other, and on the products of other districts and nations, for the supply of their needs. This industrial division and concentration gives increased importance to commerce, without which there could be no industrial development. It is thus that these two activities are separating the elements of society in order to bind them the more firmly together. The improvement of roads, rivers, harbors, the construction of canals, railroads, and telegraphs, the development of industry, the extension of commerce, the advance of general culture, and the consequent increase of human wants, is making society a very complicated structure;--indeed, it has nerve and tissue, and is becoming very sensitive. The loss of a crop in one country affects all other countries. The burning of a city, or even of a great manufacturing establishment, is really felt to the remotest ends of civilization. A commercial crisis on either shore of the Atlantic shocks the whole civilized world. A rebellion in the United States is affecting the agriculture of the whole country, the production of a staple on three continents, manufacturing in France and New and Old England, commerce everywhere. Every partisan clique, every political court and cabinet, even political destiny itself, throughout the whole world, reels with every surge of a distant revolution! How different from the condition even of Europe in the twelfth century, when a whole city or barony, an entire kingdom, or half the continent even, might have sunk beneath, the ocean, and the rest of the world have known nothing of it by its social results!