On  the  Cost  of  Agricultural  Buildings. 
565 
additions  to  or  deductions  from  the  contract,  should  form  part  of 
the  contract ; and  as  the  builder  cannot  beforehand  know  whether 
additions  will  be  made,  or  deductions  required,  the  schedule  of 
prices  will  in  all  probability  be  a fair  one. 
The  next  points  to  ascertain  are,  whether  the  work  is  properly 
performed,  and  the  material  used  of  the  quality  stipulated  for  ; 
in  ascertaining  which,  the  following  hints  will  be  found  useful. 
The  materials  used  in  a building  should  form  part  of  its  struc- 
tural strength,  and  should  not  merely  increase  the  ponderousness 
of  the  general  mass.  This  can  only  be  guarded  against  by  the 
skill  of  the  designer,  and  is  not  the  business  of  the  workmen. 
It  is  of  first  importance  that  the  foundations  be  secure — they 
should  bear  with  unflinching  firmness  the  superstructure  to  be 
raised  upon  them, — the  grand  object  being  to  secure  the  requisite 
stability  with  the  least  expenditure.  When  compelled  to  employ 
artificial  means  to  enable  the  earth  to  sustain  the  superincumbent 
weight  of  the  building  firmly,  concrete  will  be  found  an  excellent 
material  for  the  purpose.  It  should  be  composed  of  fresh  burnt 
stone  or  grey  chalk-lime,  ground  to  powder  without  slaking,  and 
gravel,  broken  stone,  or  small  pebbles,  with  a small  quantity  of 
sand  in  a dry  state,  added  ; and  afterwards,  water  sufficient  in 
quantity  to  bring  it  to  the  consistency  of  mortar  when  ready  for 
use.  After  turning  the  whole  over  with  a shovel  until  it  is  well 
blended,  it  will  be  ready  for  use,  and  should  be  used  immediately, 
for  if  it  sets  before  it  is  used  it  is  valueless. 
Various  opinions  are  prevalent  as  to  the  relative  proportions  of 
lime,  sand,  and  gravel ; but  the  best  is  considered  to  be  when  one 
of  lime  to  six  or  seven  of  gravel  or  pebbles,  including  sand,  is  used ; 
the  sand  should  be  in  proportion  to  the  gravel  as  two  or  three  to 
one,  none  of  the  gravel  being  larger  than  a full-sized  walnut. 
The  concrete  should  be  about  9 inches  wider  than  the  footings  of 
the  several  walls,  about  12  inches  in  thickness,  and  the  upper 
surface  laid  perfectly  level. 
Bricks  should  be  hard,  sound,  well  shapen,  thoroughly  burnt, 
and  of  uniform  size.  A well  burnt,  hard,  sound  brick  has  a 
peculiar  ring  when  two  are  knocked  together  ; whereas  soft,  badly 
burnt  bricks  are  of  a spongy  nature,  unsuitable  for  buildings,  soon 
fall  to  pieces  from  the  action  of  the  weather,  or  on  knocking  two 
of  them  against  each  other.  In  laying  bricks  stability  and  beauty 
are  obtained  by  regularity.  No  four-course  should  exceed  12 
inches  in  height ; they  should  be  well  bonded  together,  that  is, 
connected  by  being  placed  in  juxta-position,  every  fourth  brick 
being  laid  transversely  to  the  wall.  The  mortar  should  be  bedded 
evenly,  and  all  the  joints  between  the  bricks  well  filled  with  it : it 
should  be  composed  of  one  portion  of  lime  to  three  of  sand. 
Stone  for  walls  for  agricultural  buildings  is  only  used  in  districts 
