ON  ALUMINIUM, 
123 
double  chloride  runs  out  from  the  condenser  in  a  stream,  and  is 
collected  in  a  receiver  ;  it  becomes  solid  when  cold. 
The  reaction  is  so  complete  that  no  chlorine  is  lost.  It  has 
already  been  manufactured  at  a  cost  of  eight  cents  per  pound, 
but  the  operations  were  carried  on  to  a  very  limited  extent.  It 
is,  however,  clearly  (to  be)  demonstrated  that,  with  works  of  suffi- 
cient size  and  a  proportional  economy  in  manufacture,  the  dou- 
ble chloride  of  aluminium  and  sodium  can  can  be  produced  at  a 
cost  not  exceeding  four  and  a  half  cents  per  pound. 
In  the  manufacture  of  sodium  Mr.  Monier  has  made  considera- 
ble improvement ;  it  has  already  been  produced  at  a  cost  of 
twenty-five  cents  per  pound. 
In  the  manufacture  of  zinc,  (by  the  Belgian  process)  one  re- 
tort produces  about  thirteen  pounds  of  metal  in  24  hours.  In 
the  manufacture  of  sodium  the  reduction  is  so  quick  that  52  pounds 
of  this  metal  can  be  produced  in  a  retort  of  the  same  size  in  the 
same  space  of  time. 
The  reduction  of  zinc  costs  from  two  to  two  and  a  quarter 
cents  per  pound.  The  amount  of  ore  necessary,  being  from  a 
half  to  three-quarter  cents  per  pound.  Giving  for  the  cost  of 
one  pound  of  metal  about  three  to  three  and  a  quarter  cents. 
The  reduction  of  sodium  costs  about  ...  4  cents  per  pound. 
The  carbonate  of  soda,  2J  lbs.,  at  4  cts.  .    .10    "  " 
Giving  for  total  cost  of  one  pound  of  sodium,  14  " 
Sodium  can  be  manufactured  on  as  large  a  scale  as  zinc,  and 
when  the  workmen  have  the  same  practical  experience  in  the 
manipulations,  the  price  of  reduction  will  be  still  further  reduced, 
so  that  the  difference  between  it  and  zinc  will  be  that  of  the  first 
cost  of  carbonate  of  soda  and  the  zinc  ore. 
It  has  already  been  shown  that  the  double  chloride  of  alumi- 
,  nium  and  sodium  can  be  produced  at  a  very  low  price  ;  metallic 
sodium  can  also  be  made  very  cheaply  ;  the  reduction  is  readily 
effected  in  accordance  with  the  theory,  but  the  difficulty  in 
uniting  the  metallic  globules  of  aluminium  when  formed,  is  ob- 
viated by  stirring  at  this  point  with  a  rod,  and  the  destruction  of 
the  metal  by  the  alkaline  scoria  is  prevented  by  adding  to  the 
charge  of  the  double  chloride  of  aluminium  and  sodium,  chloride 
of  sodium  and  metallic  sodium,  either  fluoride  of  calcium  (fluor 
spar,)  or  cryolite. 
