390 
ME.  FAIEBAIEN  ON  THE  EESISTANCE  OE  TUBES  TO  COLLAPSE. 
collapse  them.  In  these  experiments  it  was  found  that  flues  35  feet  long  were  distorted 
with  considerably  less  force  than  others  of  a similar  construction  25  feet  long.  This 
anomalous  result  led  to  further  inquiry,  which  being  far  fi’om  satisfactory,  the  present 
series  of  experiments  were  instituted,  with,  it  is  beheved,  very  conclusive  results. 
In  order  to  have  every  facility  for  conducting  these  experiments,  application  was  made 
to  the  Directors  of  the  North-Eastern  Division  of  the  London  and  North-Western  Eail- 
way,  for  permission  to  conduct  them  under  their  large  octagonal  engine-house  at  Long- 
sight,  near  Manchester,  where  the  necessary  pumps  and  cranes  were  at  hand.  To  this 
request  the  Directors  gave  their  cordial  assent,  and  in  this  position  I had  the  beneflt  of  the 
suggestions  and  experience  of  Mr.  J.  Eamsbottom,  the  Company’s  engineer,  and  also  the 
constant  attendance  of  Mr.  E.  B.  Loxgeidge,  the  engineer  and  chief  inspector  to  the 
Association  for  the  Prevention  of  Boiler  Explosions.  To  both  those  gentlemen  I tender 
my  best  acknowledgements  for  the  able  and  efiicient  assistance  I have  received  from 
them  during  the  whole  time  occupied  in  conducting  the  experiments. 
To  attain  the  objects  of  the  experiments  in  a satisfactory  manner,  it  was  necessary  that 
the  apparatus  should  be  of  great  strength  and  of  dimensions  capable  of  receiving  tubes 
of  considerable  length  and  diameter.  Eor  this  purpose  a cast-hon  cylinder  was  prepared. 
8 feet  in  length,  28  inches  in  diameter,  and  2 inches  thick  of  metal,  for  the  reception 
of  the  tubes  to  be  experimented  upon.  This  cylinder,  C,  Plate  XXVIII.,  was  placed 
upon  some  balks  of  timber,  in  one  of  the  locomotive  pits,  immediately  under  the  shear- 
legs  A,  A,  for  the  convenience  of  lifting  and  replacing  the  hea's-y  cover  of  the  cylinder, 
which  had  to  be  removed  at  the  close  of  each  experiment.  A small  pipe,  a,  a,  con- 
nected the  force-pump,  B,  with  the  interior  of  the  cyhnder ; and  another,  b,  b,  commu- 
nicated with  the  steam-pressure  gauges  at  c,  which  exhibited  the  pressui’e  in  the  cylin- 
der during  the  experiment  in  lbs.  per  square  inch : to  ensure  accm’acy  two  gauges  were 
employed,  one  of  Schaepfee’s  and  the  other  of  Smith’s  construction,  and  the  mdications 
of  these  were  checked  by  an  accurate  safety-valve,  d.  A small  cock,  e,  served  to  let  off 
the  air  contained  in  the  cyhnder  when  necessary. 
Fig.  I is  a section  of  the  large  cylmder.  The  top  and  bottom  covers,  f and  g,  were 
made  of  strength  proportionate  to  that  of  the  cylinder,  to  which  they  were  secured  by 
I-inch  bolts  placed  3 inches  apart.  In  the  bottom  cover,  a hole  was  chilled,  to  , 
receive  the  rod  and  screw-nut  k,  which  supported  the  tube  D to  he  experimented  upon ; : 
and  through  the  top  passed  a 2^-inch  pipe,  m,  inserted  in  the  cast-hon  end  of  the  tube  D. 
On  the  end  of  this  pipe  was  a large  nut,  which  screwed  down  upon  an  indian-rubber  i 
Avasher  on  the  cover  of  the  cylinder,  so  as  to  close  the  opening  round  the  pipe  and  make  I 
it  water-tight.  The  object  of  this  pipe  Avas  to  alloAv  the  air  from  the  ulterior  of  the  i 
tube  D to  escape  during  the  collapse,  and  so  to  place  it,  as  nearly  as  possible,  imder  the  i 
same  circumstances  as  the  flue  of  a boiler.  ^ ' 
The  whole  of  the  experiments  Avere  effected  by  means  of  the  hydraulic  pump,  by  I 
Avhich  water  was  forced  through  the  pipe  a a into  the  cylinder  C ; thus  driAing  the  air  j 
in  a highly  compressed  state  to  the  upper  part  of  the  cylinder,  Avhence,  Avhen  a very  high  I 
