214     ICE  ;  ITS  COLLECTION,  STORAGE  AND  DISTRIBUTION. 
1.  Ice  Houses. — These  vary  in  size  and  capacity  from  two  to 
fifty  thousand  tons.  Allowing  forty  cubic  feet  of  ice  to  the  ton, 
the  smaller  size  mentioned  would  require  internal  dimensions  of 
one  hundred  feet  in  length,  fifty  feet  in  width,  and  twenty- four 
feet  in  height  to  the  eaves.  Houses  for  ten  to  thirty  thousand 
tons  are  often  built  in  several  sections,  of  these,  or  even  increased 
dimensions,  giving  one  the  idea  of  half  a  dozen  large  barns  ce- 
mented together  at  the  sides,  each  section  having  its  own  indi- 
vidual roof,  reminding  one  of  the  board  fences  one  sometimes 
sees,  where  the  upper  edge  of  the  fence  is  sawn  out  into  pickets, 
looking  like  saw  teeth.  The  capacity  of  the  houses  is  of  course 
determined  by  the  amount  of  business  the  proprietor  has,  or  an- 
ticipates. Those  examined  by  the  writer  are,  as  a  general  thing, 
entirely  clear  in  the  interior,  no  space  being  taken  up  by  beams 
or  ties,  or  anything  which  would  interfere  with  the  regular  filling 
up  of  the  whole  space  with  ice,  or  anything  which  can  possibly 
act  as  a  heat  conductor  in  the  summer  season.  An  interesting 
problem  as  to  the  lateral  pressure  of  the  ice  is,  however,  suggest- 
ed by  the  occurrence  mentioned  in  the  Boston  Journal,  of  an  ice 
house  in  the  State  of  New  York  bursting  from  the  weight  of  fifty 
thousand  tons;  and  another  query  might  be  raised  as  to  the  con- 
struction of  the  house. 
The  walls  of  most  ice  houses  are  constructed  with  a  double  row 
of  stanchions  or  studs,  the  interior  ones  being  perpendicular,  and 
the  exterior  slightly  inclined,  so  that  the  space  between  the 
boarding  may  gradually  diminish  from  twenty-four  inches  at  the 
bottom  to  sixteen  at  the  top.  The  boarding  is  put  on  between 
the  inner  and  outer  stanchions,  to  secure  it  from  being  burst  off 
by  the  pressure  of  the  filling,  and  the  inner  and  outer  shells  are 
bound  together  at  regular  intervals  by  iron  bolts,  to  prevent  them 
from  spreading  apart  from  the  same  cause.  The  space  thus  left 
is  filled  with  spent  tan  preferably,  but  sawdust  may  be  used,  or 
what  are  called  short  shavings.  The  whole  is  surmounted  by  a 
roof  with  a  steep  double  pitch,  and  the  building  is  often  white- 
washed, roof  and  all,  more  perfectly  to  reflect  the  rays  of  the 
sun.  One  sine  qua  non  is,  that  all  round  the  foundations  the 
whole  building  shall  be  perfectly  air-tight ;  not,  as  one  would  at . 
first  imagine,  to  prevent  the  access  of  air,  but  to  prevent  the 
