414 
ON  THE  MANUFACTURE  OF  ALUMINIUM. 
and  mixed.  The  liquor  became  brown,  and  a  precipitate  was 
speedily  formed.  On  leaving  the  mixture  during  the  night,  the 
surface  was  found  covered  with  a  thin  pellicle  of  reduced  silver, 
and  deposited  was  found  some  oxide  of  silver.  It  thus  became 
clear  that  the  tannic  acid  had  not  only  the  power,  as  was  expected, 
of  reducing  the  nitrate  of  silver  to  oxide,  but  had  further  reduced 
a  portion  of  the  oxide  itself  to  the  metallic  state. 
One  of  the  pills  before  mentioned,  having  become  quite  hard, 
was  triturated  with  distilled  water,  and  the  liquid  filtered.  To 
the  filtrate  was  added  a  chloride — not  the  least  trace  of  chloride 
of  silver  was  observed ;  to  another  portion  of  the  filtrate  was 
added  sulphuretted  hydrogen,  without  the  least  change  of  color. 
It  may,  we  think,  therefore,  be  fairly  deduced  that  such  a 
compound  is  decidedly  incompatible,  at  least  as  far  as  the  chemis- 
try of  the  compound  is  concerned.  The  therapeutical  view  of  the 
matter  must  be  left  to  the  judgment  of  the  medical  practitioner, 
there  being  many  compounds  which,  although  composed  of  in- 
compatible elements,  are  not,  necessarily,  therapeutically  incom- 
patible.— Ibid, 
ON  THE  MANUFACTURE  OF  ALUMINIUM. 
By  M.  H.  St.  Claire  Deville. 
The  following  is  the  substance  of  a  paper  presented  to  the 
French  Academy  at  the  session,  June  18th,  1855,  and  published 
in  No.  25  of  the  Comptes  Bendus. 
The  author  stated  that  he  had  the  honor  of  presenting  to  the 
Academy  the  first  specimens  of  aluminium  that  he  had  prepared 
at  the  Javel  Chemical  Works,  under  the  patronage  of  the  Em- 
peror, at  his  expense,  by  a  process  which  he  describes.  He  con- 
siders that  manufacturing  processes  have  been  attained  for  the 
production  of  chloride  of  aluminium  and  sodium,  the  materials 
used  in  the  fabrication  of  aluminium. 
He  obtains  the  chloride  of  aluminium  by  acting  on  a  mixture 
of  alumina  and  coal  tar,  previously  calcined,  with  chlorine,  which 
is  readily  effected  in  a  common  gas  retort,  the  layer  of  the  mix- 
ture being  from  four  to  eight  inches  thick,  which  is  readily  pene- 
trated by  the  gas.  The  chloride  is  condensed  in  a  chamber  of 
glazed  brick  work.  Obtained  in  this  way  it  is  a  crystallized  compact 
substance  of  a  sulphur  yellow  color,  of  considerable  density  and  but 
slightly  ferruginous.    This  contamination  is  removed  by  passing 
