CARBONIC  ACID  WATER  APPARATUS. 
108 
4.  Into  another  portion  of  the  fluid  sulphuretted  hydrogen 
was  passed.  The  water  instantly  became  chocolate  brown.  On 
boiling  it,  a  black  precipitate  was  formed,  which,  on  being 
washed,  was  found  to  be  insoluble  in  cyanide  of  potassium. 
5.  Chromate  of  potash,  added  to  another  portion  of  the  fluid, 
yielded  a  gamboge  yellow  precipitate,  which  was  soluble  in  pot- 
ash,   (Colorless  ilocculi  remained  in  the  otherwise  clear  liquid. ) 
6.  Sulphuric  acid  rendered  the  filtered  concentrated  liquid 
(1,)  slightly  milky;  and  after  some  time,  a  white  precipitate  fell. 
7.  In  the  same  liquid  (1,)  iodide  of  potassium  produced  a  fine 
yellow  precipitate. 
Thus  experiments  4,  5,  6  and  7,  all  concurred  in  proving  the 
presence  of  lead  in  the  water. 
8.  On  the  addition  of  ferro- cyanide  of  potassium  to  the  fil- 
trate cf  4,  a  blue  tinge  was  given  to  the  liquid. 
9.  On  adding  the  same  re- agent  (Cfy-j-2K)  to  the  acid  liquid, 
a  clear,  pea  green  color  was  produced,  deepening  in  shade,  until 
it  changed  to  a  fine  ultramarine  blue.  A  blue  precipitate  fol- 
lowed, leaving  the  supernatant  liquid  of  a  pea  green  color. 
I  have  no  authorities  at  hand  which  would  justify  any  definite 
conclusions  from  the  reactions  in  experiments  8  and  9 ;  but  re- 
lying upon  my  own  examinations  of  solutions  of  tin  with  ferro- 
cyanide  of  potassium,  I  did  not  hesitate  to  infer  the  presence  of 
this  metal  in  the  soda-water.  (I  may  refer  to  the  reactions  of 
Cfy-f  2K  and  Sn  more  particularly  at  another  time.) 
To  recapitulate :  the  soda-water  contained  lead  and  tin,  but 
no  copper  or  other  metal  sought  for. 
Richmond,  Indiana,  12th  mo.  24th,  1855. 
REMARKS  ON  A  CARBONIC  ACID  WATER  APPARATUS. 
By  the  Editor, 
•Carbonic  acid  water,  under  the  name  of  "  Mineral  Water  "  and 
"  Soda  Water,"  is  becoming  every  year  more  extensively  into 
use  as  a  beverage  in  the  warmer  season  of  the  year,  and,  as  when 
pure,  it  is  perhaps  the  least  objectionable  of  all  substitutes  for 
pure  cold  water,  its  preparation  is  necessarily  a  subject  of  some 
importance  to  that  numerous  body  of  apothecaries  throughout 
the  country  who  keep  it  on  sale.  In  large  cities  and  towns  the 
preparation  of  carbonic  acid  water  has  become  a  distinct  busi- 
