power plant, kilowatt capacity of dynamos, and number of incandescent lamps are greater for the composite stations. The fact that such public utilities as water and gas are so often operated by municipalities which also operate electric stations explains this condition. Nearly four-fifths of the purely electric central stations and more than three-fifths of those in the composite group were commercial stations. Exclusive of the item of arc lamps, about 6 per cent of the income and equipment of the purely electric group was reported by the municipal stations, as compared with about 10 per cent for these stations in the composite group. TABLE 5.-PURELY ELECTRIC AND COMPOSITE CENTRAL ELECTRIC STATIONS, BY CHARACTER OF Includes 2 stations classed as "Other forms of ownership," in order that the operations of individual stations may not be disclosed. 2 Exclusive of 275,079 lamps used by the central stations to light their own electric properties. 3,295 3 The number of incandescent lamps was largely an estimate and, although mostly reported on a 16-candlepower basis, embraces a considerable number ranging from 2 to 50 candlepower. Table 6 presents a comparative summary of the purely electric and the composite plants for 1907 and 1902. The percentages of increase for the composite stations are much greater than for the purely electric, but the absolute increases show no such excess. On the contrary, the purely electric stations show a greater absolute increase for all the leading items. It is noteworthy that both the commercial and the municipal stations share in the uniformly larger percentages of increase for the composite stations, which appears to indicate that the distinctive characteristics of the two classes of stations are much less marked than formerly. TABLE 6.-PURELY ELECTRIC AND COMPOSITE CENTRAL ELECTRIC STATIONS-COMMERCIAL AND MUNICIPAL: 1 Exclusive of auxiliary engines with a total capacity of 65,823 horsepower in 1907 and 14,454 horsepower in 1902. 2 Decrease. 3 Exclusive of 275,079 lamps used by the central stations to light their own electric properties in 1907. These lamps were not reported separately in 1902. The number of incandescent lamps was largely an estimate and, although mostly reported on a 16-candlepower basis, embraces a considerable number ranging from 2 to 50 candlepower. "Not reported separately in 1902. Relationship of population and central stations.-As a rule, the central electric stations are concentrated in the most populous states and at points within these states from which the largest percentage of the population can be served economically. From Table 119 it appears that New York, Pennsylvania, Illinois, and Ohio, the 4 states having the largest population, containing together 29.6 per cent of the total for the United States, reported 1,296 electric stations, or 27.5 per cent of the total number in operation during 1907, and the annual output of these stations amounted to 2,553,745,890 kilowatt hours, or 43.6 per cent of the output of all stations in the United States. While the proportionate number of central stations and the proportionate population of this group of states were very nearly the same, or less than one-third of the total, their proportion of the kilowatt-hour output formed nearly one-half of the total. In 1902 the exact percentages for these items were as follows: Population, 29.7 per cent; number of establishments, 30.8 per cent; and kilowatt-hour output, 49.1 per cent. A number of the tables contained in this report present the statistics by the officially adopted geographic divisions. An outline and a list follow, showing the states and territories contained in each division: The largest proportion of the total population of the country, 33.9 per cent in 1907 and 34.5 per cent in 1902, was in the North Central states. These states also contained nearly the same percentage of electric lamps wired for service, but for the horsepower of primary-power plants, kilowatt capacity of dynamos, and output of stations, the percentages were considerably less. The North Atlantic states were next in the proportion of population, with 27.8 per cent in 1907 and 27.7 per cent in 1902, but their proportions for the various items of the central-station industry for both 1907 and 1902 were much larger, as follows: Horsepower of primary-power plant, 37.4 and 44.2 per cent, respectively; kilowatt capacity of dynamos, 38.9 and 42.7 per cent; output of stations, 42.4 and 50.6 per cent; number of arc lamps, 43.6 and 44 per cent; and number of incandescent lamps, 41.5 and 47.1 per cent. The South Atlantic and South Central divisions, treated as a single group, embraced 32.7 per cent of the population in 1907 and 32.4 per cent in 1902. Although their proportions of the various items of the central-station industry were larger in 1907 than in 1902, they were the smallest shown for any section of the country. The exact percentages for each of these two divisions for 1907 and 1902 were as follows: South Atlantic, population, 13.5 and 13.7 per cent, respectively; horsepower of primary-power plant, 7.2 and 5 per cent; kilowatt capacity of dynamos, 7.2 and 5.1 per cent; output of stations, 4.5 and 4.1 per cent; number of arc lamps, 4.9 and 4.5 per cent; and number of incandescent lamps, 4.6 and 3.4 per cent. The South Central, population, 19.1 and 18.6 per cent; horsepower of primary-power plant, 6 and 6.4 per cent; kilowatt capacity of dynamos, 6.1 and 6.8 per cent; output of stations, 4.4 and 6.1 per cent; number of arc lamps, 7.2 and 6 per cent; and number of incandescent lamps, 6.5 and 5.6 per cent. The Western division was the smallest in population, with 5.6 per cent of the total in 1907 and 5.5 per cent in 1902. Its percentages of the various items for the centralstation industry for 1907 and 1902, respectively, were as follows: Horsepower of primary-power plant, 19.6 and 15.2 per cent; kilowatt capacity of dynamos, 18 and 14.4 per cent; output of stations, 23.8 and 13.4 per cent; number of arc lamps, 7.6 and 7.8 per cent; and number of incandescent lamps, 13 and 10 per cent. TABLE 7.-CENTRAL ELECTRIC STATIONS-RELATION OF LEADING ITEMS TO POPULATION, BY GEOGRAPHIC DIVISIONS: 1907 AND 1902. 1 Based upon Bureau of the Census estimates. 2 Includes capacity of auxiliary engines, amounting to 65,823 horsepower in 1907 and 14,454 horsepower in 1902. 3 In 1907, exclusive of 162,338 lamps of "Other varieties-Nernst, vacuum, vapor, etc."-the revenue for which is included with the income for lighting, and 275,079 lamps used by the central stations to light their own electric properties. These lamps were not reported separately in 1902. The number of incandescent lamps was largely an estimate and, although mostly reported on a 16-candlepower basis, embraces a considerable number ranging from 2 to 50 candlepower. The comparison of the population of these geographic divisions with the several items of Table 7 representing the equipment and output of the stations may be roughly summarized as follows: The North Central, one-third of all items; the North Atlantic, one-fourth of the population and two-fifths of the other items; the South Atlantic and South Central combined, one-third of the population and one-eighth of the other items; and the Western, one-twentieth of the population and one-sixth of the other items. Comparing the proportion of population with that for the number of stations, the proportion of stations was larger than that for population for the North Central and Western divisions, and smaller for the North Atlantic, South Atlantic, and South Central divisions. One of the most pronounced features of the centralstation industry is the large per capita showing for the Western division, the output of stations and all the items of equipment, except arc lamps, being the largest of any group. The Western division, having, in 1907, less than 5,000,000 population, as compared with a population of upward of 11,000,000 and 16,000,000 for the South Atlantic and South Central divisions, respectively, reported a greater primary horsepower, a larger dynamo capacity, and more incandescent lamps wired for service than the two latter divisions combined. In per capita showing, the North Atlantic division was second in rank, the North Central third, the South Atlantic fourth, and the South Central fifth. Mention has already been made of the fact that numerous tables in the report for 1902 contained statistics for the central stations, grouped according to the population of the places in which the stations were located. Such a presentation of the statistics is interesting, but the following points should be considered in connection with the results: 1. The reports for the central stations are assigned to the places in which the plants are located. 2. The development of the alternating current by means of the single-phase or polyphase dynamo, referred to in the report of 1902, has continued since that census, until at the census of 1907 the kilowatt capacity of this class of machines represented 82 per cent of the total dynamo capacity of all central stations. In many instances large plants are now located at places where water power is available for the generation of the current, but at great distances from the places where the current is used. It is evident that any attempt to arrive at the true per capita consumption of current, and other features based on population by localities, should include the statistics for these generating plants, but this is impossible, since they frequently furnish current to two or more widely separated cities, mills, or factories. The following are among the most notable examples of this phase of the development and use of electrical energy: In California two companies have plants located in several small places where water power is available for the generation of electricity, which is not only transmitted to the largest cities in the state but is used in numerous smaller places in the course of its transit. In New York the electrical energy generated at Niagara Falls is distributed to various cities and towns in the state. In South Carolina there is one large company with generating plants at places where there is water power, from which places the electrical energy is transmitted to various sections of that state. If necessary, many other instances of this character of electric service might be given, but these are deemed sufficient for the purpose. 3. Some electric companies, though owning two or more central stations situated in widely separated places, made but one report covering all of their properties. As a rule, such reports are assigned to the place in which the principal plant is located. In some instances these plants are in two or more of the groups of cities for which separate statistics were shown in 1902, and the assignment of all of them to a certain city or group of cities would detract from the value of conclusions based upon population. A majority of the central stations, however, are located in the cities to which they are assigned and where all of their output, or the major portion, is consumed. While, therefore, this grouping of the stations in 1902 by population may have been instructive to some extent, the defects are too great, so far as relates to the commercial stations, to warrant such an analysis at the census of 1907. Statistics are presented, however, for the following 34 selected cities, grouped in four classes according to size: In the selection of these 34 cities, the rule followed was to limit them to those in which all the electrical energy used was practically generated within their respective limits and but little, if any, sold for outside consumption. Although the selection was to some extent an arbitrary one, the cities are fairly representative of the various sections of the country. These 34 cities contained 75 stations in 1907 and 70 stations in 1902, the character of ownership of which in 1907 was as follows: Corporate, 61; and municipal, 14. In 1902, 58 were corporate; 11, municipal; and 1, individual. |