150 
The  Detection  of  Methylated  Ether. 
( Am.  Jour.  Pharm 
\     March,  1886. 
In  pharmaceutical  preparations  in  which  methylated  ether  is  present, 
it  can  also  be  detected,  though  the  presence  of  alcohol  interferes  with 
the  process,  and  more  care  is  requisite  than  in  merely  deciding  whether 
a  sample  of  ether  is  methylated  or  not. 
A  convenient  apparatus  consists  of  a  Glyusky's  distillation  tube 
(with  a  thermometer)  attached  to  a  flask  heated  by  a  water-bath,  and 
connected  with  a  Liebig's  condenser,  the  source  of  heat  being  a  burner 
of  small  size,  so  that  the  water  in  the  bath  may  be  slowly  heated. 
The  following  table  exhibits  results  obtained  with  an  arrangement 
of  this  description,  by  adopting  a  process  of  limited  fractional  distilla- 
tion; and  removing  the  graduated  tube  in  which  the  distillate  was 
collected  at  the  moment  the  thermometer  indicated  90°  F.  The  lighter 
portions  of  methylated  ether  carry  over  much  heavier  ether,  which 
considerably  augments  the  volume  of  the  distilled  portion. 
The  results  are,  obviously,  in  no  sense  quantitative,  being  dependent 
on  the  particular  samples  and  apparatus  employed.  They  serve,  how- 
ever, to  show  the  modifying  influence  of  pure  ether  and  of  rectified 
spirit. 
100  c.c.  of  each  taken. 
Rectified  ether  specific  gravity  720  
•730  
Methylated  ether  specific  gravity  717.. 
"        "         "  720.. 
.730;; 
Rectified  (735)  and  methylated  (730) 
equal  parts  
Sp.  JEtheris  B.P. 
(Rectified  spirit  and  methylated  ether 
C730))  
Tr.  Lobelix  JEther. 
(Rectified  spirit  and  methylated  ether 
Collod'aun  B.P. 
(Rectified  spirit  and  methvlated  ether 
(730)  )  
Boiled  freely  at  74°  F. 
After  cooling  and  again  heat- 
ing, a  further  5  c.c.  obtained. 
Whilst  it  is  easy  to  detect  ordinary  methylated  ether,  it  is  clearly 
impossible  to  determine  in  the  case  of  a  liquid  of  correct  boiling  point, 
whether  such  a  sample  has  been  prepared,  as  the  British  Pharmacopoeia 
directs,  from  rectified  spirit,  or  separated  by  careful  fractional  rectifica- 
tion from  ether  originally  made  from  methylated  spirit.— jPharrn. 
Jour,  and  Trans.,  Feb.  6,  1886,  p.  663. 
