PRODUCTION  OP  NITRATE  OF  SODA  AT  IQUIQUE  (PERU).  265 
He  then  proceeds  to  separate  the  "  costra  "  and  "  cora " 
from  the  "  caleche,"  throwing  aside  all  the  latter  that  he  does 
not  believe  to  contain  more  than  ten  or  twelve  per  cent,  of 
nitrate  :  it  is  then  broken  into  smaller  lumps,  to  be  conveyed  to 
the  "  paradas."  A  refinery  of  nitrate  is  called  an  "  Officina," 
and  is  generally  placed  in  the  centre  of  the  calecheros  or  nitrate 
grounds,  and  consists  of  one  or  more  paradas  ;  a  paradas  is  a 
pair  of  round  iron  boilers,  each  holding  from  70  to  300  gallons  ; 
these  are  placed  together,  in  rough  stonework,  with  a  fire-place 
between  them.  At  the  parada,  the  acendrador  breaks  the  lumps 
into  pieces  about  the  size  of  a  fist,  and  rejects  the  inferior  pieces, 
so  as  to  bring  the  whole  to  about  25  to  34  per  cent,  of  nitrate.  It 
is  now  thrown  into  the  boilers  with  a  quantity  of  water ;  after 
boiling  some  two  or  three  hours,  the  fondeador  (boiler)  continu- 
ally stirring  the  mass,  supposing  that  the  caleche  is  by  that  time 
exhausted,  throws  out  the  ripio  (refuse,)  adds  more  caleche  and 
mother  water ;  and,  after  boiling  some  two  or  three  hours,  a 
well  saturated  solution  is  obtained  ;  it  is  then  by  hand  baled  into 
a  deposit,  from  whence,  as  soon  as  the  mud  and  salts  are  de- 
posited, it  is  baled  into  shallow  coolers,  where  it  crystallizes.  The 
mother  water  is  then  drawn  off,  and  the  nitrate  thrown  out  to 
dry.  The  paradas  are  charged  twice  a-day,  and  the  daily  pro- 
duct is  from  fifteen  to  twenty  quintals  of  nitrate,  containing 
about  3  per  cent,  of  impurities,  chiefly  common  salt.  The 
average  cost  of  a  quintal  of  nitrate  is  :— 
Barretero,  breaking  out        ....        12^  cents. 
Acendrador,  assorting 
Fondeador,  boiling  .... 
Powder  for  blasting  .... 
Asses  bringing  the  caleche  to  the  paradas 
20  lbs.  coals  at  $1.50  per  quintal  . 
Wear  and  tear  of  parada,  reparations,  and  depre- 
ciations ...... 
•2 
H 
H 
3 
30 
29i 
$1.00 
This  system  of  making  nitrate  is  the  same  as  was  first  adopted 
at  the  commencement  of  the  trade,  and  unquestionably  well 
adapted  for  that  early  period,  having  the  advantage  of  being 
simple,  easily  understood  and  worked;  yet  it  is  still  continued 
