METALLIC  TUNGSTEN. 
465 
quantities  have  become  too  small  to  admit  of  further  continuance 
of  the  process. 
This  process  has  been  in  constant  use  in  my  laboratory  during 
the  last  three  years.  In  this  time  it  has  been  applied  in  the  study 
of  petroleums,  coal  oils,  the  more  volatile  parts  of  coal-  and  wood- 
tars,  the  essential  oil  of  cumin,  commercial  fusel  oil,  from  corn 
whiskey,  and  even  to  mixtures  more  complex  than  either  of 
these.  As  the  result  of  this  long  experience,  I  can  say  that,  as 
regards  bodies  not  decomposed  by  heat  in  distillation,  I  have  not 
yet  found  a  mixture  so  complex  that  it  may  not  be  resolved  by 
this  process  into  its  proximate  constituents  so  completely,  that 
these  shall  have  almost  absolutely  constant  boiling-points.  In 
repeated  instances,  even  from  petroleums,  I  have  obtained  these 
constituents  so  pure,  that  the  contents  of  an  ordinary  tubulated 
retort  charged  with  one  of  them  has  been  comparatively  distilled 
off  without  any  essential  change  of  temperature ;  i.  e.,  not  to 
the  amount  of  J°  C,  the  thermometer  frequently  remaining 
absolutely  constant  for  more  than  half  an  hour,  a  constancy  of 
boiling-point  not  exceeded  by  that  of  distilled  water.  This  state 
of  purity,  I  think  I  may  safely  assert,  has  never  before  been 
attained  from  such  mixtures,  by  any  system  of  fractional  distilla- 
tion. 
As  I  soon  shall  be  prepared  to  present  to  the  Academy  de- 
tailed results  of  the  investigations  above  referred  to,  I  may  omit, 
further  allusion  to  them  on  this  occasion. 
I  would  remark,  in  conclusion,  that  it  seems  to  me  not  imgr.ob* 
able  that  this  process  may  ultimately  prove  to  be  of  great  value 
in  the  arts.  It  is  not  too  much  to  anticipate  that,  whenever,  the-; 
various  constituents  of  the  mixtures  referred  to  shall  have  been 
separately  and  thoroughly  studied  in  a  pure  state,  some  of  them 
may  be  found  to  possess  properties  which  will  give  to  them  great 
commercial  value,  sufficient  to  justify  the  expenditure  necessary 
to  separate  them  in  large  quantities. 
METALLIC  TUNGSTEN. 
We  learn  that  a  Swedish  metallurgist  has  discovered  a  method 
of  reducing  tungsten,  by  which  he  obtains  it  at  once  in  a  state  of 
30 
