24  Practical  Notes  from  Foreign  Journals, 
PRACTICAL  NOTES  FROM  FOREIGN  JOURNALS. 
By  Hans  M.  Wilder. 
Cahe  White  (Face  Powder). — Oxide  of  zinc  4,  rice  starch  4,  white 
French  chalk  4,  calcined  plaster  of  Paris  1 ;  rub  well  together,  and 
mix  with  sufficient  water  to  suitable  consistence  so  that  it  can  be 
poured  out  into  boxes  or  paper  moulds  (if  in  moulds,  cut  to  proper 
size  and  sliape  after  5  to  10  minutes). — Pharm.  Zeit.  RussL,  xxii,  p.  6. 
Oils  of  Cassia  and  Cinnamon  may  be  distinguished  by  their  specific 
gravity.  The  former  has  1*0366,  and  the  latter  1*0097. — Rundschau, 
viii,  p.  768. 
Carbon  Diffuses  through  Porcelain. — Violle  has  observed  that  if  a 
porcelain  crucible,  inserted  into  a  black  lead  crucible,  be  heated  to 
about  1,500°C.  (melting-point  of  palladium),  the  latter  will  look  as 
light  colored  as  if  made  of  clay,  while  the  porcelain  crucible  is  quite 
black. — Ber.  d.  Deutsch.  Ges.,  xv,  p.  275. 
Paper  and  leather  may  be  rendered  very  pliable  by  soaking  in  a 
solution  of  1  part  of  acetate  of  sodium  or  potassium  in  4  to  10  parts 
of  water,  and  drying. — Polyt.  Notizbl.,  xxxvii,  p.  365. 
Citric  Acid  Freed  of  Iron. — During  the  Turco-Russian  war  some 
40,000  pounds  of  citric  acid  got  contaminated  with  iron  and  zinc. 
Meyke  found  that,  by  converting  the  acid,  by  means  of  chlorinated 
lime,  into  citrate  of  calcium,  and  decomposing  the  latter  with  sulphu- 
ric acid,  he  succeeded  in  obtaining  a  perfectly  pure  acid.  To  a  cold 
filtered  solution  of  16  parts  contaminated  acid  in  96  parts  distilled 
water  was  added  about  21  parts  chlorinated  lime,  previously  reduced 
to  a  thin  paste.  After  quickly  straining,  the  liquid  was  heated  to 
boiling,  separating  completely  the  citrate  of  calcium,  while  the  chlo- 
ride of  iron  and  zinc  remained  in  solution.  The  magma  was  trans- 
ferred to  a  strainer,  and  washed  completely  with  boiling  hot  water  till 
ammonium  sulphhydrate  ceased  to  indicate  metals.  To  the  citrate  of 
calcium  (about  20  parts)  was  added  about  60  parts  of  diluted  sulphu- 
ric acid  (1:5),  under  constant  stirring,  and,  lastly,  heating  to  boiling. 
After  complete  decomposition  the  solution  of  pure  citric  acid  was 
filtered  from  sulphate  of  calcium,  evajwrated  to  syrupy  consistence, 
let  stand  for  some  hours,  decanted  from  the  sedunent,  and  evaporated 
further  in  water-bath.  Crystallization  was  hastened  by  dropping  a 
small  crystal  of  citric  acid  into  the  cooled  liquid.  Meyke  obtained  from 
