FOOTNOTES:

[A] Presented at the meeting of May 18th, 1910.

[B] Transactions, Am. Soc. C. E., Vol. LX, p. 1.

[C] Engineering News, July 1st, 1909.

[D] From "Gravel for Good Roads."

[E] Transactions, Am. Soc. C. E., Vol. LXVIII, pp. 58-60.

[F] "Discoveries and Inventions of the Nineteenth Century," by Robert Routledge, Assistant Examiner in Chemistry and in Natural Philosophy to the University of London.

[G] Engineering News, January 15th, 1909.