────────────────────────────────────────────────────────────────┬────── Character of Material │Factor ────────────────────────────────────────────────────────────────┼────── Clay, gravel and boulders, Medford │22–26 Mostly sand, deep trenches sheeted. Wages medium. Richland │ Center. │21–22 Sandy clay. Wages medium. Labor conditions good at Kiel. │15–20 Sand. _Sandy_ clay, some water. Labor conditions good. Pipe │ prices medium at Manston. │14–20 Gravelly clay, ⅒th laid in concrete at Burlington. │13–22 Sandy clay, some water, sheeting at La Farge. │17–23 Sand with water. │ 20 Gravel and boulders. High wages. │ 26 Clay soil. Good digging. │ 17 Sandy clay. Some water. │ 23 Clay 2 miles inland. Laborers boarded at sanitarium, Wales │ 35 Clay, gravel and boulders at Plymouth. │20–27 Sand, clay and good digging at Lake Mills. │16–19 Red clay. Machine work at North Milwaukee. │20–24 Good digging. Wages medium at West Salem. │17–19 Sandy soil, bracing only required. No water. Wages and pipe │ medium. │ 14 Red sticky clay. │ 24 Good digging in any soil. Work scarce. │ 15 Red clay. No bracing. │ 20 Work inland from railroad. Boarding laborers _and_ other │ expenses. │ 35 ────────────────────────────────────────────────────────────────┴────── Second: To find the cost of 15–inch pipe at a depth of 9.0 feet, enter the diagram at a diameter of 15 inches and continue down until the intersection with a depth of trench at 9 feet is found. Now go diagonally parallel to lines running from left to right upwards to the intersection with the diagonal line running from left to right downwards corresponding to the factor of 11 found above. The vertical line passing through this point shows the cost to be 67 cents per foot. TABLE 3 COST OF SEWER CONSTRUCTION AT ATLANTIC, IOWA (From Gillette’s Handbook of Cost Data) Material: Clay, not difficult to spade and requiring little or no bracing and practically no pumping. All hand work except backfill which was done by team and scraper. Depth of trench averaged 8.2 feet; width 30 inches. Diameter of pipe 10 inches.