248 Modern Business Geography On Tye + Fy rr —r =e J 29 2! al Mins il ons aN 29K oY vw YAO NEED Toto 3 J Pm dL J UNITED STATES DISTRIBUTION OF POPULATION a: ; 10d Fig. 164. The region marked A has a population of 80 or more to the square mile; B, between 30 and 40 to the square mile; C, 40 and 10; D, below 10. The circles give the number to the square mile in the different states. Which state has the highest figure? the lowest? What two regions are marked C? From this map and the map on the opposite page, where should you ex- pect the railway network to be closest? Verify your answer by reference to Figure 128, page 176. Are the states of the wheat belt and the corn belt among the most populous? smith shops and repair shops, are needed even in farming regions to keep all kinds of machinery and tools in repair. Sawmills are needed to supply building material, and gristmills to grind the grain which is grown almost everywhere. Each city must also have bakeries, for people demand fresh bread and pastry. Gas for lighting and heating is usually produced locally, because the coal from which it is made can be transported and stored more cheaply than can the gas, which re- quires special pipes and tanks. All modern cities and many small towns also have electric light plants to provide power both for lighting and for trolley lines, and for use in small shops and homes. These universal manufacturing industries, as we may call them, form a large part of the manufacturing in the more lightly shaded areas of Figure 165, and are of great importance in the heavily shaded areas where other types of manufacturing are also prominent. MANUFACTURING TN NORTHEASTERN UNITED STATES The northeastern quarter of the United States adds to these univer- sal industries many others, which differ greatly from place to place. More than 30 per cent of all the gainfully employed workers in the states from Maine and Marvland westward to the Mississippi River