=21. Density of Population.=—So far the study of population has been confined to the entire city. It is frequently necessary to predict the population of a district or small section of a city. A direct census may be taken, or more frequently its population is determined by estimating its density based on a comparison with similar districts of known density, and multiplying this density by the area of the district. In determining the density, statistics of the population of the entire city will be helpful but are insufficient for such a problem. A special census of the area involved would be conclusive but is generally considered too expensive. A count of the number of buildings in the district can be made quickly, and the density determined by approximating the number of persons per building. Statistics of the population of various districts together with a description of the character of the district are given in Table 5.
FIG. 9.—Density, Area, and Population, Cincinnati, Ohio. 1850 to 1950. ]
────────────┬────────────────────────────────────────┬────────┬──────── City │ Character of District │ Area, │Density │ │ Acres │per Acre ────────────┼────────────────────────────────────────┼────────┼──────── Philadelphia│Thomas Run. Residential. Mostly pairs of│ │ │ two and three-story houses. 1204 acres│ │ │ settled. │ 1,840│ 59 │Pine Street. Residential. Mostly solid │ │ │ four to six-story houses. 156 acres │ │ │ settled. │ 160│ 97 │Shunk Street. Residential. Mostly pairs │ │ │ of two and three-story houses. 539 │ │ │ acres settled. │ 539│ 119 │Lombard Street. Tenements and hotels, │ │ │ 145 acres settled. │ 147│ 113 │York Street. Residential and │ │ │ manufacturing. 354 acres settled. │ 358│ 94 │ │ │ New York │Residential. Three-story dwellings with │ │ City │ 18–foot frontage, and four-story flats│ │ │ with 20–foot frontage. │ │ 100 │Residential. Five-story flats. │ │520–670 │Residential. Six-story flats. │ │800–1000 │Residential. Six-story apartments. High │ │ │ class. │ │ 300 │ │ │ Chicago │1st Ward. Retail and commercial. The │ │ │ “Loop”. │ 1,440│ 20.5 │2d Ward. Commercial and low-class │ │ │ residential solidly built up. │ 800│ 53.5 │3d Ward. Low-class residential. │ 960│ 48.1 │5th Ward. Industrial. Some low-class │ │ │ residences. Not solidly built up. │ 2,240│ 25.51 │6th Ward. Residential. Four and │ │ │ five-story apartments. A few detached │ │ │ residences. │ 1,600│ 47.0 │7th Ward. Same as Ward 6. Not solidly │ │ │ built up. Contains a large park. │ 4,160│ 21.7 │8th Ward. Industrial. Sparsely settled. │ 13,624│ 4.8 │9th Ward. Industrial and low-class │ │ │ residential. Solidly built up. │ 640│ 70.0 │10th Ward. Same as Ward 9. │ 640│ 80.8 │13th Ward. Low-class residential. │ │ │ Solidly built with three and │ │ │ four-story flats. │ 6,100│ 36.7 │16th Ward. Middle-class residential. │ │ │ Some industries. Well built up. │ 800│ 81.5 │19th Ward. Industrial and commercial. │ │ │ Some low-class residences. │ 640│ 90.7 │20th Ward. Low-class residential. Some │ │ │ industries. Entirely built up. │ 800│ 77.1 │21st Ward. Industrial. Entirely built │ │ │ up. │ 960│ 49.9 │23d Ward. Industrial and residential. │ 800│ 55.4 │24th Ward. Residential apartment houses │ │ │ and middle-class residences. │ 1,120│ 46.8 │25th Ward. Residential. High-class │ │ │ apartments. Wealthy homes. Contains a │ │ │ large park. │ 4,160│ 24.0 │26th Ward. Residential. Middle-class │ │ │ homes and apartments. Fairly well │ │ │ built up. │ 4,640│ 16.1 │27th Ward. Residential. Sparsely │ │ │ settled. │ 20,480│ 5.5 │29th Ward. Low-class residential. │ │ │ Two-story frame houses. “Back of the │ │ │ Yards”. │ 6,400│ 12.8 │30th Ward. The Stock Yards. │ 1,280│ 40.1 │32d Ward. Scattered residences. │ 8,480│ 8.3 │33d Ward. Scattered residences. │ 12,944│ 5.5 │35th Ward. Scattered residences. │ 4,960│ 12.0 │ │ │ General │The most crowded conditions with │ │ average │ five-story and higher, contiguous │ │ │ buildings in poor class districts. │ │750–1000 │Five and six-story contiguous flat │ │ │ buildings. │ │500–750 │Six-story high-class apartments. │ │300–500 │Three and four-story dwellings, business│ │ │ blocks and industrial establishments. │ │ │ Closely built up. │ │100–300 │Separate residences, 50 to 75–foot │ │ │ fronts, commercial districts, │ │ │ moderately well built up. │ │ 50–100 │Sparsely settled districts and scattered│ │ │ frame dwellings for individual │ │ │ families. │ │ 0–50 ────────────┴────────────────────────────────────────┴────────┴────────