___________________________________________________________________________ | | | | || | | | Pressure |III_{1}|III_{3}|III_{3}|III_{3}||III_{2}|III_{4}|III_{4}|III_{4} per square|Earth. |Earth. |Water. | Total ||Earth. |Earth. |Water. | Total foot at | | | | earth || | | | earth | | | | and || | | | and | | | | water.|| | | | water. __________|_______|_______|_______|_______||_______|_______|_______|_______ | | | | || | | | A | 575 | 510 | 100 | 610 || 1,350 | 810 | 140 | 950 B | 400 | 350 | 190 | 540 || 900 | 540 | 260 | 800 C | 200 | 175 | 280 | 455 || 450 | 270 | 380 | 650 __________|_______|_______|_______|_______||_______|_______|_______|_______ ___________________________________________________________________ | | | | || | | | Pressure |IV_{1}|IV_{3}|IV_{3}|IV_{3}||IV_{2}|IV_{4}|IV_{4}|IV_{4} per square|Earth.|Earth.|Water.|Total ||Earth.|Earth.|Water.|Total foot at | | | |earth || | | |earth | | | | and || | | | and | | | |water.|| | | |water. __________|______|______|______|______||______|______|______|______ | | | | || | | | A | 1,370| 1,210| 100 | 1,310|| 3,175| 1,910| 150| 2,060 B | 1,170| 1,030| 200 | 1,230|| 2,700| 1,610| 290| 1,900 C | 970| 855| 290 | 1,145|| 2,250| 1,355| 430| 1,785 D | 775| 680| 370 | 1,050|| 1,800| 1,100| 570| 1,670 E | 590| 515| 460 | 975|| 1,350| 820| 710| 1,530 F | 400| 350| 560 | 910|| 900| 540| 860| 1,400 G | 190| 170| 650 | 820|| 450| 275| 1,000| 1,275 __________|______|______|______|______||______|______|______|______ FOOTNOTES: [Footnote A: Presented at the meeting of May 18th, 1910.] [Footnote B: _Transactions_, Am. Soc. C. E., Vol. LX, p. 1.] [Footnote C: _Engineering News_, July 1st, 1909.] [Footnote D: From "Gravel for Good Roads."] [Footnote E: _Transactions_, Am. Soc. C. E., Vol. LXVIII, pp. 58-60.] [Footnote F: "Discoveries and Inventions of the Nineteenth Century," by Robert Routledge, Assistant Examiner in Chemistry and in Natural Philosophy to the University of London.] [Footnote G: _Engineering News_, January 15th, 1909.] DISCUSSION