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


T. KENNARD THOMSON, M. AM. SOC. C. E.--Although the author
deserves great credit for the careful and thorough manner in which he