VIRGINIA 



giBUXIXMH 



Figure 6. 



-Plan or Harpers Ferry bridge as built by Latrobe. 

 Winchester track was later removed, 



I he - 



engineering. It furnished the means of expression 

 for such men as Knight, Wright, Whistler, l.ntrobe, 

 and Win in-.. 



Of these pioneer civil and mechanical engineers, 

 some were formally trained but most were self-taught. 

 Bollman's careei on the B. & ( ), is of particulai interest 

 not only because he was perhaps the most successful 

 of the latter class Inn because he was probably also 

 the last. Il<- ma) In- said to lie a true representative 

 mi the transitional period between intuitive and exai t 

 ering. Actually, his designing was a composite 

 of the two methods. While making consistent use 

 of mathematical analysis, he was at the same time 



more or less dependent upon empirical methods 

 For 5 ears. B. & O. employees told stories of his sessions 

 in the tin shop of the railroad's main repait fi 



i Mount ('lair in Baltimore, where he built models 

 of bridges from scraps of metal and then tested them 



i e truction to locate weaknesses. It seems most 

 likely, however, that the empirical studies were used 

 solely as c hei ks against the mathematical. 



In the period when Bollman b aing about 



lstn there were fewei than ten men in the country 



designing bridges by scientificall) correct analytical 



ods, Whipple and Roebling the most notable of 



this group. By 1884, the year of Bollman's death. 



7, Receni m Bollman's Winchestei span. Only two of the 



three lines of trussing arc shown. I he model is based on Bollman's published 

 cription and drawings of the structure. (USNM 318171; Smithsonian 



PAP] R 36: ENGIM I KIM. « < iN IRIBI I H )NS O] Ul N!>l I BO] I MAN 



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