In  much  the  same  regal  way  the  managers  of
a  railroad  order  a  steel  bridge  flung  across  a
chasm  in  the  midst  of  a  wilderness  far  from
civilisation,  or  command  that  a  new  structure
shall  be  substituted  for  an  old  one  without
disturbing  traffic;  and,  lo  and  behold,  it  is  done
in  a  surprisingly  short  time.  But  the  new
bridges,  in  contrast  to  the  old  ones,  are  as  spider
webs  compared  to  the  overarching  branches  of
a  great  tree.  The  old  type,  built  of  solid
masonry,  is  massive,  ponderous,  while  the  new,
slender,  graceful,  is  built  of  steel.
133


STORIES  OF  INVENTORS

One  day  a  bridge-building  company  in
Pennsylvania  received  the  specifications  giving
the  dimensions  and  particulars  of  a  bridge  that
an  English  railway  company  wished  to  build
in  far-off  Burma,  above  a  great  gorge  more  than
eight  hundred  feet  deep  and  about  a  half-mile
wide.  From  the  meagre  description  of  the
conditions  and  requirements,  and  from  the
measurements  furnished  by  the  railroad,  the
engineers  of  the  American  bridge  company
created  a  viaduct.  Just  as  an  author  creates
a  story  or  a  painter  a  picture,  so  these  engineers
built  a  bridge  on  paper,  except  that  the  work
of  the  engineers'  imagination  had  to  be  figured
out  mathematically,  proved,  and  reproved.
Not  only  was  the  soaring  structure  created  out
of  bare  facts  and  dry  statistics,  but  the  thickness
of  every  bolt  and  the  strain  to  be  borne  by
every  rod  were  predetermined  accurately.
And  when  the  plans  of  the  great  viaduct  were
completed  the  engineers  knew  the  cost  of  every
part,  and  felt  so  sure  that  the  actual  bridge  in
far-off  Burma  could  be  built  for  the  estimated
amount,  that  they  put  in  a  bid  for  the  work
that  proved  to  be  far  below  the  price  asked  by
English  builders.
