GLEANINGS  FROM  GERMAN  JOURNALS. 
239 
short  time  separate  from  it  lustrous  crystals  ;  after  twelve  hours 
the  sides  of  the  glass  vessel  are  covered  with  beautiful  orange 
red  needles,  often  a  centimeter  in  length,  which  are  obtained 
pure  simply  by  washing  with  cold  alcohol ;  they  are  insoluble  in 
water,  alcohol,  ether  and  sulphide  of  carbon.  From  the  ele- 
mentary analysis,  the  following  formula  is  calculated :  C42H22N2 
O4,  HgSg.  Treated  with  concentrated  sulphuric  acid,  the  crystals 
lose  their  color,  and  on  the  addition  of  a  little  water  sulphate  of 
strychnia  is  dissolved,  and  colorless  transparent  oily  drops  of 
persulphide  of  hydrogen  are  separated,  which  are  slowly  decom- 
posed into  sulphur  and  sulphide  of  hydrogen. 
Quinia,  cinchonia  and  brucia  do  not  yield  an  analogous  com- 
pound. An  alcoholic  solution  of  2-03  grm.  strychnia  yielded 
after  twelve  hours  2-287  grm.  of  the  red  crystals  =  87*2  p.  c. 
of  the  theoretical  quantity.  The  author  suggests  that  this  com- 
pound might  probably  be  serviceable  for  obtaining  pure  strychnia 
from  mixtures,  &c. — Qliem.  Centralhlatt,  1868,  p.  846,  from 
Ber.  d.  deutschen  chem.  Gresellsch.  i,  81. 
Coloring  matter  of  Claret. — A.  Phillips  states  that  sesqui- 
chloride'of  iron  imparts  to  the  juice  of  black  cherries,  huckleberries 
and  mallows  a  violet  color  with  a  reddish  or  bluish  tint.  Pure 
claret,  on  the  contrary,  is  colored  red  brown.  The  amount  of 
free  acid  in  the  wine  influences  the  shade  of  the  color.  The 
bluish  grey  color  imparted  by  artificially  colored  wines,  accord- 
ing to  Boettger,  to  sponges  previously  treated  with  muriatic 
acid,  is  probably  due  to  their  retaining  a  trace  of  ferric  chloride. 
— Ibid.,  p.  864,  from  Journ.  f.  praht.  Chem.  ci,  320. 
Estimation  of  potassa  for  technical  laboratories. — Plun  Rett 
proposed  bitartrate  of  soda  for  this  purpose.  Gladisz  and  Balo 
found  that,  from  pure  solutions,  the  precipitation  of  the  potassa 
is  the  more  complete,  the  greater  the  amount  of  the  reagent 
added.  The  potassa  of  5  c.  c.  of  a  solution  containing  10  p.  c. 
saltpetre  was  completely  precipitated  by  50  c.  c.  of  a  saturated 
solution  of  bitartrate  of  soda,  while  on  using  10  c.  c.  of  the  for- 
mer and  20  of  the  latter  solution,  2-5  p.  c.  less  than  the  amount 
of  saltpetre  was  found.  Cream  of  tartar  is  more  soluble  in 
water  and  jn  nitrate  of  soda  than  in  bitartrate  of  soda.  The 
