Am.  Jour.  Pharm. 
Jan. 1876. 
Varieties. 
35 
named  gasogen,  which  furnished  in  twenty-four  hours  1,000  to  1,200  cubic  metres 
of  purified  gas,  the  cost  of  which,  independent  of  labor,  and  of  the  cost  and 
depreciation  of  plant,  he  calculates  as  follows  : — 
For  100  Cubic  Metres  of  Gas. 
f.  c. 
75  kilos  of  coke  at  0*03  franc  .  .  .  .  2  25 
55    "         coal  at  0*025    "  .  .  .137 
82    "         lime  .  .  .  .  .82 
4  44 
The  material  costs,  therefore,  4J  centimes  per  cubic  metre. 
Instead  of  decomposing  water  by  carbon,  certain  other  processes  have  recently 
come  into  use,  and  require  notice. 
Lenoir's  process,*  suggested  in  1867,  is  of  very  limited  applicability.  He 
decomposed  barium  sulphide  with  water,  obtaining  sulphate  of  baryta  and 
hydrogen — BaS-f-4H20=BaS04-f-4H2.  This  process  is  only  practicable  where  the 
manufacture  of  barium  sulphate  (permanent  white)  is  the  main  object,  and  the 
hydrogen  a  by-product,  as  was  the  case  with  Lenoir. — Chem.  Nevus,  Sept.  17  to  Oct.  8. 
VARIETIES. 
Vegetable  Mucilage.  By  W.  Kirchner  and  B.  Tollens. — The  authors,  after 
a  critical  review  of  the  various  investigations  that  have  been  made  in  connection 
with  this  subject,  describe  their  process  for  the  purification  of  the  mucilage,  which 
is  very  similar  to  Schmidt's.  The  mucilage,  after  the  addition  of  hydrochloric  acid, 
is  precipitated  by  alcohol  and,  when  the  operation  has  been  repeated  six  or  eight 
times,  the  product  is  repeatedly  washed  with  absolute  alcohol,  and  finally  with  ether. 
By  this  means  the  ash  is  reduced  to  a  minimum,  and  the  mucilage,  when  dried,  is 
obtained  as  a  porous  mass,  and  not  in  hard  lumps. 
Quince  mucilage  was  obtained  principally  from  quince  seeds,  by  digesting  them  in 
water  for  four  hours,  then  rubbing  them  through  a  hair  sieve,  boiling,  and  straining 
through  linen.  After  purification  it  is  greyish-white  and  swells  up,  when  soaked  in 
water,  to  a  gelatinous  mass,  forming  a  mucilaginous  solution  only  on  the  addition 
of  a  small  quantity  of  potassium  hydrate.  It  still  contains  4  to  5  per  cent,  of  min- 
eral matter,  and  on  analysis  gives  numbers  corresponding  with  the  formula  C18H28Ou. 
When  it  is  boiled  with  dilute  sulphuric  acid,  white  flocks  are  precipitated,  and  sugar 
and  dextrin  or  gum  are  produced.  From  the  results  of  numerous  carefully  con- 
ducted quantitative  experiments,  it  would  seem  that  the  flocculent  precipitate  of 
cellulose  is  nearly  constant  after  the  first  half-hour,  however  long  the  boiling  may  be 
continued,  but  the  percentage  of  gum  gradually  decreases,  whilst  that  of  the  sugar 
increases  within  certain  limits,  showing  the  conversion  of  the  former  into  the  latter. 
The  gum  polarizes  laevorotary ;  the  sugar,  which  reduces  cupric  solution,  dextro- 
*  Lenoir,  Wagn.  Jahresbcr.,  1867,  219,  259. 
