We have now considered with some detail the disposition of the streets and avenues surrounding the intense business center of Chicago. While this outer city area is occupied mainly by dwellings, certain streets along which transportation lines pass, come to be lined with shops throughout their entire length, so that one passes from the center of affairs into the residence district without noting the transition. As a rule, however, the density and importance of the buildings decrease from the center to the circumference; and in corresponding manner the highways of circulation and exchange may diminish in width. It is essential, however, to provide encircling or belt thoroughfares which act as collectors of traffic, and also as distributors of it; so as to prevent the inextricable congestion which inevitably arises when masses of people gathered along converging lines attempt to penetrate the center at a single point. However difficult it may be to provide against such congestion in the case of older cities, a reasonable system of circulation in connection with the business center of a comparatively new city like Chicago should be accomplished with comparative ease. The widening of some streets and the construction of needed arteries is made less difficult by reason of the fact that the buildings which cover the greater part of Chicago’s area beyond the business center are not of a permanent character, and in the natural order of things they must be replaced by others more substantial. Provision should be made now so as to ensure that, as the transformation progresses, sufficient land area shall be left unoccupied to provide good sanitary conditions, and attractive streets as well. The three requisites for this outer region, therefore, are: first, convenient means of access to the main business center and to the subordinate centers, which are the day’s working-places; secondly, equally convenient means of access to the water and the fields and forests, where the hours of recreation and refreshment are passed; and, thirdly, as much light and air as possible for the dwellings and the schools, where the home-keepers are occupied with their daily tasks, and where the children are trained, either for weakness or for strength, as physical conditions largely determine. [Illustration: CVIII. CHICAGO. VIEW OF THE SOUTH SHORE LOOKING SOUTH EAST OVER GRANT PARK.] FOOTNOTES: