554  Manufacture  of  Carbonate  of  Soda,  etc.  {^-^X^ST 
The  portion  of  real  tea  ash  which  is  insoluble  in  water  is  almost  en- 
tirely soluble  in  hydrochloric  acid. 
Very  many  uses  may  be  made  of  a  determination  of  the  ash  in  a 
sample  of  tea.  As  an  example  of  what  may  be  learnt-  from  such  de- 
terminations, I  will  cite  an  imaginary  case,  which,  however,  finds  its 
parallel  in  practice.  Let  us  supp  ose  that  the  tea  yielded  the  normal 
proportion  of  ash,  viz.,  5-75  per  cent,  on  the  air-dried  leaves,  and  let 
us  suppose  that  one-third  of  this  consisted  of  sand.  With  these  data 
before  him  the  analyst  would  be  justified  in  finding,  not  only  that 
there  was  a  little  sand  in  the  tea,  but  that  at  least  one-third  of  the 
sample  did  not  consist  of  genuine  tea,  but  either  of  some  other  kind 
of  leaf  or  of  spent  tea  (which  is  not  so  rich  in  ash  as  genuine  tea). 
On  a  future  occasion  I  hope  to  publish  further  researches  on  tea, 
and  will  conclude  with  an  expression  of  my  conviction  that  a  little 
careful  chemical  work  bestowed  on  the  subject  of  tea  will  render  the 
examination  of  it  highly  certain  and  satisfactory. — Chem.  News,  Oct. 
10,  1873. 
A  REVOLUTION  IN  THE  MANUFACTURE  OF  CARBONATE 
OF  SODA. 
By  Dr.  Rudolph  Wagner. 
Six  years  ago,  when  the  international  jury  at  the  Paris  Exposition 
expressed  their  opinion  upon  the  state  of  the  soda  industry  at  that 
time,  all  the  judges,  whether  practical  or  theoretical  men,  believed 
that  Leblanc's  process  would  hold  the  field  for  a  long  time  yet.  This 
seemed  still  more  probable  since  a  process  had  just  been  introduced 
for  recovering  the  sulphur  from  the  soda  residues.  At  that  time  all 
the  soda  in  use  was  prepared  by  this  process,  excepting  a  compara- 
tively small  amount  obtained  from  Chili  saltpetre  and  cryolite,  al- 
though there  were  already  tangible  indications  that  soda  could  be 
made  on  a  large  scale  by  another  method  which  would  be  cheaper 
than  Leblanc's  process. 
The  chemical  section  of  the  international  jury  at  the  Vienna  Expo- 
sition, under  the  presidency  of  Prof.  A.  W.  Hofmann,  constituted  a 
congress  of  chemical  technology.  By  its  labors  during  the  course  of 
the  summer  this  congress  of  scientific  men  was  able  to  authenticate 
the  very  important  fact  that  although  Leblanc's  process  might  in  the 
future  possess  some  importance  for  certain  branches  of  the  industry, 
yet  in  most  places  another  soda  process  would  be  introduced  in  the 
