PREFACE TO THE SECOND EDITION 



THE demand for this book has, in three months, exhausted 

 the first printing, <md seems to indicate thereby the interest in 

 and need of such a book on the part of engineers and teachers. 

 The author, therefore, thought it wise to take advantage of this 

 opportunity to make certain revisions in order to bring the book 

 up to date, and to include the latest alterations by those 

 societies and associations which are quoted herein. 



Slight changes have accordingly been made in the following 

 bpecifications: Railroad Bridges, Materials and Workmanship, 

 and Cement. J. C. 0. 



NEW YORK, December, 1910. 



VI 



