VI

PREFATORY NOTICE.

)

unusual magnitude, will be found in Sections VI.and VII. The descriptions are completely illus-trated by explanatory sketches, and a folio volumeof plates of a novel character as applied to workson engineering; and the process of construction isfaithfully perpetuated in a series of tinted lithographsfrom sketches with the camera lucida.

These were the limits originally intended for thiswork.

It was impossible, however, to proceed even thusfar without some explanation of the principles appliedin the investigation of the strength of beams.

At the suggestion, therefore, of many excellentfriends, the Author was subsequently induced toattempt a more complete explanation of the natureof transverse strain, embodying, as far as he wasable, the views entertained by Mr. Stephenson onthis subject, and the practical information accumu-lated during a period of four years in the superin-tendence of a work so entirely novel, and in whichbeams of every variety, and of unprecedented mag-nitude, have been so extensively employed.

In accordance with these views, a general expo-sition of the Theory of Beams is given in Section III.;and, in continuation of the subject, much new, andit is hoped valuable, information has been addedin Section IV., in which an extensive experimentalinvestigation of the strength of materials, as employedin construction, will be found.

Section VIII. is devoted to the application of thegeneral reasoning contained in the preceding cliap-

i