VARIETIES. 
463 
used  for  the  concentration,  is  owing  to  the  presence  of  nitrogen  compounds; 
and  besides  this,  it  appears  that  sulphuric  acid  containing  nitric  acid,  is 
less  suited  to  the  purification  of  oils  than  pure  acid. — Pharmaceutical  Jour- 
nal, from  Ann.  de  Chim.  et  de  Phy.,  3  ser.  vol.  2,  p.  47. 
Crayons  for  Writing  on  Glass.  By  R.  Brunnquell, — The  author  pre- 
pares crayons  for  writing  on  glass,  so  as  to  enable  the  contents  of  glass 
vessels  to  be  described  immediately  upon  them  in  the  following  manner : 
Four  parts  of  spermaceti  (or  stearine),  three  parts  of  tallow,  and  two  parts 
of  wax  are  fused  in  a  cup  ;  six  parts  of  minium  and  one  part  of  potash  are 
then  stirred  into  it,  the  mass  kept  warm  for  half  an  hour,  and  then  poured 
into  glass  tubes  the  thickness  of  a  lead  pencil.  After  rapid  cooling,  the 
mass  may  be  screwed  up  and  down  in  the  tube,  and  cut  to  the  finest  point 
with  a  knife.  A  crayon  is  thus  obtained  which  will  readily  write  upon  clean 
dry  glass. — Pharm.  Journal,  from  Dingler's  Polytech.  Journal,  and  Chemical 
Gazette. 
Adulteration  of  Cassia  Oil  with  Oil  of  Cloves.  By  G.  L.  Ulex. — This 
adulteration  is  as  frequent  as  it  is  profitable.  The  specific  gravity  affords 
no  indication  of  the  purity  of  the  oil,  but  there  are  other  means  of  distin- 
guishing between  cassia  and  clove  oil.  When  a  drop  of  true  cassia  oil  is 
heated  on  a  watch-glass,  it  evolves  a  fragrant  vapor,  possessing  but  little 
acridity ;  when,  however,  clove  oil  is  present,  the  vapor  is  very  acrid  and 
excites  coughing. 
Cassia  oil,  when  treated  with  fuming  nitric  acid,  does  not  present  any 
intumescence,  but  crystallizes ;  when  clove  oil  is  present,  it  swells  up, 
evolves  a  large  quantity  of  red  vapor,  and  yields  a  thick  reddish-brown  oil. 
Cassia  oil,  treated  with  concentrated  caustic  potash,  solidifies  when  pure, 
but  not  when  mixed  with  clove  oil. 
One  or  two  drops  of  true  cassia  oil  dissolved  in  alcohol,  give  a  pure  brown 
color  on  the  addition  of  protochloride  of  iron. 
Fresh  clove  oil,  treated  in  the  same  way,  assumes  an  indigo  blue  color ; 
older  oil  becomes  green.  Both  colors  are  so  intense  that  a  twenty  or  thirty- 
fold  volume  of  alcohol  must  be  added  before  the  liquid  admits  of  the  pas- 
sage of  light.  In  this  reaction  the  protochloride  of  iron  is  reduced,  and  the 
clove  oil  is  converted  into  a  black  resin,  which  separates. 
Mixtures  of  cassia  and  clove  oils  treated  with  protochloride  of  iron,  give 
an  indefinite  color  between  brown  and  green, — Pharm.  Journ.  from  Archiv 
der  Pharmacie,  Jan.  7,  1853. 
Test  for  the  Purity  of  Ultramarine. — Dr.  Bernheim  proposes  the  following 
test  for  the  examination  of  commercial  ultramarine :  Two  ounces  of  sul- 
phuric acid  are  diluted  with  twenty  ounces  of  water ;  the  samples  of  ultra- 
marine introduced  into  separate  test  tubes  in  quantities  of  fifty  or  one 
hundred  grains,  and  the  acid  added  until  the  blue  color  is  converted  into  a 
