260 
NOTE  ON  CARBOLIC  ACID,  ETC. 
higher  boiling  point,  was  found  to  belong  to  the  cresyl  group  or 
series  of  organic  compounds  and  was  called  cresylic  acid. 
Another  liquid  found  in  creasote,  but  in  small  proportion,  and 
having  a  still  higher  boiling  point,  was  found  to  belong  to  the 
xylene  series,  and  was  called  xylic  acid.  In  proportion  as  the 
rectification  of  the  creasote  rejected  the  higher  and  lower  boiling 
point  liquids,  so  it  would  contain  more  or  less  of  these  so-called 
acids,  and  thus  would  vary  in  its  composition,  and  boiling  point. 
Subsequent  examination  proved  that  these  liquids  were  not  acids 
at  all,  and  their  composition  led  modern  chemists  to  consider 
them  as  alcohols.  For  some  time  they  were  classed  with  alco- 
hols, and  the  coal  tar  creasote  of  the  markets  was  then  regarded 
as  a  mixture,  in  varying  proportions,  of  phenyl-aleohol  and 
cresyl-alcohol,  with  small  and  unimportant  proportions  of  other 
organic  compounds. 
Still  later  investigations  by  modern  European  chemists  appear 
to  have  established  the  fact  that  they  are  not  alcohols.  Their 
composition  appears  to  be  precisely  that  of  the  alcohols,  and  this 
led  to  the  classification  of  them  as  alcohols.  Further  investiga- 
tion of  their  properties  and  combinations  shows  that  they  do  not 
behave  at  all  as  alcohols,  though  uniform  with  them  in  composi. 
tion.  The  researches  of  Kekule  upon  this  point  seem  now  to  be 
generally  accepted,  and  the  difference  in  properties  and  behaviour 
are  attributed  to  a  different  construction  of  the  molecule  from 
the  same  elements.  Upon  these  views  a  class  of  organic  co.m- 
pounds  has  been  erected  and  called  phenols,  and  the  phenyl 
compound,  or  crystallized  carbolic  acid,  under  the  name  Phenol, 
seems  to  have  been  adopted  as  the  type  of  the  class,  just  as  com- 
mon ethylic  alcohol  is  called  simply  Alcohol,  and  is  adopted  as 
the  file-leader  or  type  of  the  class  or  group  of  alcohols.  Hence 
Phenol  is  the  now  accepted  name  for  crystallized  carbolic  acid, 
or  phenylic  alcohol,  and  cresyl-phenol,  or  cresylol,  or  cresol,  is 
the  name  for  the  cresylic  acid,  or  cresylic  alcohol.  The  so-called 
xylic  acid  appears  to  have  been  less  studied,  and  its  position  is 
not  known.  If  it  be  homologous  with  the  others,  and  of  similar 
construction  of  molecule,  its  condensed  name  would  be  xylol, 
and  we  should  then  have  Phenol,  cresol  and  xylol  as  the  import- 
