Am.  Jour.  Pharm. ) 
Oct.,  1878.  / 
Varieties. 
503 
Professor  Tichborne  was  very  glad  to  find  that  Mr.  Dott  had  con- 
firmed a  fact  which  he  noticed  many  years  ago  in  a  work  called  the 
4t  Laboratory,"  which  was  afterwards  denied  by  Mr.  Chapman,  one  of 
the  main  authorities  on  nitrites.  He  then  pointed  out  that  nitrite  of 
amyl  was  dissociated  in  the  act  of  boiling  into  amylic  hydrate  and 
nitrous  oxide  gas  ;  this  was  denied,  as  he  had  stated,  by  Mr.  Chap- 
man, and  he  was  glad  to  find  that  recent  experiments  confirmed  his 
observations. 
Mr.  T.  B.  Groves  asked  if  Professor  Tichborne  had  tried  distilla- 
tion in  vacuo  or  in  carbonic  acid,  so  as  to  be  out  of  contact  with  air. 
Professor  Tichborne  said  that  at  the  time  he  performed  the  experi- 
ment he  tried  carbonic  acid,  and  that  had  no  effect ;  but  he  was  not 
prepared  to  say  what  would  be  the  result  of  distillation  in  vacuo.  He 
fancied  that  the  dissociation  of  the  molecules  was  really  a  matter  of 
temperature,  and  as  distillation  in  vacuo  could  be  carried  on  at  a  much 
lower  temperature,  that  dissociation  might  be  brought  to  nil  or  almost 
so. — Phar.  Jour,  and  Trans.  [Lond.],  Aug.  31,  1878. 
V  A  RIETI  E  S. 
A  Method  of  Distinguishing  Gallic,  Tannic  and  Pyrogallic  Acids.  By  Wm. 
Watson,  F.C.S. — To  about  \  grain  of  each  acid  in  a  little  water  add  NH^HO. 
Gallic.  Tannic.  Pyrogallic. 
Pink,  rapidly  changing  to  Same  as  gallic.  Lemon-colored  solution. 
deep  orange  solution. 
To  each  ammoniacal  solution  add  HN03. 
Gallic.  Tannic.  Pyrogallic. 
Red.  Purple  precipitate  insoluble  Red. 
in  excess. 
"Substituting  HC1  for  HNO.. 
Gallic.  Tannic.  Pyrogallic. 
Red.  Pink  precipitate  soluble       Pink,  quickly  changing  to 
in  excess.  red. 
— Phar.  Jour,  and  Trans.,  July  20,  1878. 
Process  for  the  Detection  of  Alcohol  in  Ethereal  Oils.  By  A.  Drechsler. — 
The  author  uses  a  solution  of  1  part  potassium  bichromate  in  10  parts  of  nitric 
acid  of  spec.  grav.  1*30.  The  new  reagent  shows  the  presence  of  even  the  smallest 
traces  of  alcohol  in  ethereal  oils,  as  on  its  addition  there  is  evolved,  along  with  the 
specific  odor  of  the  oil,  the  well-known  pungent  smell  of  ethyl-oxide,  whilst,  at  the 
same  time,  a  very  characteristic  change  of  color  occurs,  which  is  very  different, 
according  to  the  quality  of  the  different  ethereal  oils,  and  is  best  observed  by  using 
for  the  experiment  small  porcelain  capsules  shaped  like  a  watch-glass.  Five  to  six 
drops  of  the  oil  in  question  are  poured  into  a  capsule,  two  or  three  drops  of  the 
reagent  are  added,  and  the  whole  is  let  stand.  In  certain  oils  a  remarkably  beautiful 
jplay  of  color  appears  in  the  mixture. —  Cbem.  News,  Aug.  9,  from  Chem.  Ztg. 
