206 
GLEANINGS  FEOM  FOREIGN  JOURNALS. 
Assay  of  Glycerin. — According  to  M.  Hager  (Jour,  de  Pharm., 
Jan.,  1869,)  when  glycerin  is  falsified  with  sugar  or  dextrine  it 
may  be  detected  as  follows  :  Dilute  it  with  water,  add  molyb- 
date  of  ammonia  and  some  drops  of  nitric  acid  and  boil.  In 
case  these  impurities  are  present  the  liquid  colors  blue  ;  if  pure 
it  continues  colorless.  The  proportions  employed  are  as  follows  : 
Glycerin  5  drops,  distilled  water  100  to  120  drops,  molybdate 
of  ammonia  3  to  4  centigrammes,  pure  nitric  acid  one  drop ;  boil 
for  about  two  minutes. 
New  use  of  Mica. — M.  Puscher  has  lately  called  the  attention  of 
the  Industrial  Society  of  Nuremberg  to  the  Siberian  mica,  which  is 
found  abundantly  in  very  fine  tables,  and  which  so  far  has  only 
been  employed  for  window-lights  and  lanterns,  and  to  make  the 
cylinders  for  petroleum  oil  lamps,  and  suggests  ^various  new  uses 
of  it. 
If  after  reducing  it  to  thin  laminae  to  be  cleansed  with  sul- 
phuric acid  it  may  be  silvered  like  glass,  and  its  flexibility  ena- 
bles it  to  boused  on  curved  surfaces  for  ornament,  or  as  reflectors. 
When  such  plates  are  heated  to  a  certain  degree  in  muffles  they 
assume  an  unpolished  silver  surface,  and  may  be  wrought  into  a 
variety  of  ornaments.  When  coarsely  powdered  and  dusted  on 
surfaces  marked  in  figures  with  moist  gelatin,  a  very  brilliant 
efi*ect  is  produced. — Jour,  de  Pharmacie,  from  Cosmos. 
Presence  of  gum  in  Wine.— Ml.  Pasteur  has  recognized  the 
presence  in  all  wines,  in  variable  proportions,  but  always  very 
sensible,  of  a  substance  combined  with  phosphate  of  lime  and  hav- 
ing all  the  general  properties  of  gum,  especially  that  of  yielding 
mucic  acid  in  quantity  by  the  action  of  nitric  acid,  identical 
with  that  from  arabin.  It  may  be  separated  from  the  wine  by 
evaporating  to  one-fifteenth  its  bulk,  allowing  the  salts  to  crys- 
tallize during  24  hours,  decanting  the  syrupy  mother-water  and 
precipitating  the  gum  by  four  times  its  bulk  of  alcohol.  It 
should  be  collected  on  a  filter,  washed  with  alcohol,  redissolved  in 
water  and  reprecipitated. 
On  an  impurity  in  commercial  Chloroform. — M.  Personne,  of  the 
Hospital  of  Mercy,  has  made  known  the  nature  of  the  alteration, 
stated  by  M.  Stader  in  18(57,  in  the  chloroform  of  commerce  ex- 
