INTRODUCTION

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Two other papers from ASCE Transactions LXVIII (September 1910) are referenced in this paper:

The word “Figure” is used in two ways. It refers either to individual numbered Figures (1-21), or to any of the four pictures that make up each Plate, identified in the form “Fig. 2, Plate XXI”. Figures 1-4 are always discussed as a group.

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List of Illustrations (added by transcriber)