PRODUCTION  OF  NITRATE  OF  SODA  AT  IQUIQUE  (PERU).  263 
2d.  The  hypochlorite  of  lime,  on  the  contrary,  entered  gradu- 
ally into  solution. 
3d.  At  the  end  of  the  third  lixiviation  all  the  free  chloride 
of  calcium  was  dissolved ;  for  from  this  time  the  proportion  be- 
tween the  hypochlorite  of  lime  and  the  chloride  of  calcium  be- 
came nearly  regular. 
4th.  As  the  chloride  of  calcium  dissolves  at  once  completely, 
while  the  hypochlorite  dissolves  principally  after  the  third  lixi- 
viation, it  results  that  either  these  two  bodies  are  in  combina- 
tion, or  that  the  water  decomposes  chloride  of  lime  into  hypo- 
chlorite and  chloride  of  calcium. 
5th.  The  author  considers  that  the  hydrate  of  lime  is  com- 
bined with  the  chloride  of  calcium,  forming  a  basic  chloride. 
This  would  explain  the  reason  why  4  atoms  of  hydrate  of  lime 
take  2  atoms  only  of  chloride.  This  opinion  is  supported  by  the 
fact  that  the  crystalline  compound  3O0,CaCl-}-16H0  is  decom- 
posed by  water  into  hydrate  of  lime  and  chloride  of  calcium. 
6th.  The  author  assigns  to  chloride  of  lime  the  following 
formula  : — 
CaO,C10+CaCl,2CaO+  4HO. 
7th.  The  hydrate  of  lime  separated  when  the  chloride  of  lime 
is  treated  with  water,  retains  with  great  force  a  certain  amount 
of  hypochlorite  which  repeated  washings  will  not  remove.  In 
estimating  exactly  the  hypochlorous  acid  in  chloride  of  lime,  it 
is  necessary,  therefore,  to  value  the  deposit  with  the  solution.  For 
commercial  purposes,  however,  it  is  better  to  assay  the  clear 
solution  filtered  from  the  deposit,  as  that  alone  is  employed,  the 
deposit  being  usually  rejected. — Lon.  Pharm.  Journ.  Jan. 
1862,  from  Repertoire  de  Chimie. 
ON  THE  PRODUCTION  OF  NITRATE  OF  SODA  AT  IQUIQUE  (PERU.) 
As  Iquique  is  the  centre  of  this  trade,  and  to  it  its  present  im- 
portance is  wholly  to  be  attributed,  it  is  thought  to  be  advisa- 
ble to  convey  in  this  report  as  much  information  as  can  be 
procured  as  to  this  article,  and  in  order  that  such  information 
shall  be  truthful,  the  writer  has  availed  himself  of  the  views  of 
several  Englishmen  at  present  engaged  in  the  trade. 
About  from  six  to  fourteen  leagues  from  the  coast,  and  run- 
