AmAU0g.js92arm"}  Gleanings  from  the  German  Journals.  407 
Marine  glue,  according  to  Moniteur  industriel  (Nouv.  Retried.,  April, 
8/92,  iv)  is  prepared  as  follows:  About  450  gm.  of  caoutchouc 
are  dissolved  in  18  litres  of  benzol.  When  solution  has  taken  place 
and  the  mixture  assumed  the  consistency  of  a  thick  cream,  which  it 
usually  does  after  about  10  days,  shellac  is  added  equal  to  two  or 
three  times  the  weight  of  the  solution.  The  mixture  is  heated  and 
run  into  plates.    The  glue  is  used  at  a  temperature  of  1200  C. 
GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
By  Frank  X.  Moerk,  Ph.G. 
Iodine-absorption  of  oils  and  fats. — The  method  given  in  detail 
in  the  American  Journal  of  Pharmacy,  1892,  page  79,  in  which 
it  was  recommended  to  use  four  times  as  much  iodine  as  was  likely 
to  be  absorbed,  has  been  modified,  further  research  establishing  that 
twice  the  amount  of  iodine  was  sufficient.  The  modified  method 
answering  for  all  fats  and  oils  is  as  follows  :  About  0*150  gm.  are 
dissolved  in  10  cc.  chloroform,  10  cc.  each  of  iodine  and  mercuric 
chloride  solutions  are  added  and  allowed  to  stand  two  hours  ;  after 
adding  20  cc.  potassium  iodide  solution  and  IOO-150  cc.  water,  the 
excess  of  iodine  is  titrated  with  sodium  thiosulphate  solution.  If 
in  the  determination  it  be  found  that  the  blank  test  requires  less 
than  twice  the  quantity  of  thiosulphate  solution  used  in  the  case  of 
the  oil  or  fat,  the  determinations  must  be  repeated,  using  20  cc.  each 
of  iodine  and  mercuric  chloride  solution  for  o  150  gm.  oil  or  fat. — 
D.  W.  Fahrion,  Chemiker  Ztg.,  1892,  862. 
To  determine  alkalinity  ofLabarraques  Solution,  etc. — N.  G.  Blattner 
proposes  several  methods  :  (1)  25  cc.  are  diluted  with  50-IOO  cc. 
water  and  after  adding  water  of  ammonia  in  excess  the  mixture  is  gradu- 
ally heated  until  the  reaction  has  ceased,  when  the  liquid  can  be  boiled 
to  dryness  and  redissolved  in  water  to  make  250  cc.  Of  this  solution, 
ICO  cc.  (=  10  cc.  original  preparation)  can  be  directly  titrated  with 
standard  sulphuric  or  hydrochloric  acid,  using  methyl-orange  as 
indicator.  By  using  methyl-orange  and  phenolphthaleine  it  is  possible 
to  determine  separately  the  alkalinity  due  to  sodium  hydrate  and 
sodium  carbonate.  (2)  10  cc.  of  the  preparation  are  diluted  with 
water,  a  few  drops  phenolphthaleine  added  and  titrated  with  normal 
sulphuric  acid ;  it  may  be  necessary  to  add  a  drop  of  phenolphthaleine 
solution  from  time  to  time  to  determine  if  the  alkali  has  been  neu- 
