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ON  THE  COMPOSITION  OF  CREOSOTE. 
of  gold  and  platinum,  with  fir  chips  moistened  with  muriatic  acid 
and  with  nitrate  of  silver,  it  behaved  exactly  like  the  creosote 
investigated  by  the  author,  but  dissolved  completely  and  readily 
in  dilute  solution  of  potash  and  in  ordinary  acetic  acid.  By  long 
standing  in  the  air  it  acquires  a  tinge  of  yellow,  and  when  dis- 
solved in  concentrated  solution  of  potash  it  becomes  slightly 
brownish,  but  grows  gradually  darker  and  darker  until  it  has 
attained  a  dark  brown  color.    Its  analysis  gave — 
I.  IT.  III. 
C        74-76  74-98  74-85  24  =  144  75.39 
H         7-78        7-84  7-78  15  15  7-85 
0        17-17  17-48  17-37  4  32  16-76 
As  this  creosote  was  purified  exactly  according  to  Yolckel's 
directions,  it  is  clear  that  the  author's  creosote  could  not  be 
identical  with  YolckeFs.  Both  crude  products,  however,  were 
certainly  obtained  from  wood  tar  by  Reichenbach's  method, 
whence  it  follows,  that  the  products  obtained  in  this  way  may 
vary.  According  to  Yolckel,  in  order  to  obtain  a  creosote  free 
from  certain  volatile  oils  which  contaminate  the  commercial  pro- 
duct, and  of  the  composition  found  by  him,  the  boiling  with  solu- 
tion of  potash  must  be  continued  until  the  turbid  distillate 
becomes  perfectly  clear  on  the  addition  of  dilute  solution  of 
potash  ;  and  the  solubility  of  creosote  obtained  by  his  method  in 
ordinary  acetic  acid,  and  in  very  dilute  solution  of  potash,  is  to 
be  regarded  as  a  sign  of  its  purity.  The  author  continued  the 
boiling  with  solution  of  potash  until  the  turbid  distillate  again 
became  perfectly  clear  on  the  addition  of  dilute  solution  of 
potash  ;  and  creosote,  purified  by  him  in  accordance  with  Yolckel's 
method,  was  readily  and  completely  soluble  in  very  dilute  solu- 
tion of  potash  and  in  ordinary  acetic  acid,  but  nevertheless  it 
possessed  a  different  composition.  Solubility  in  acetic  acid  and 
dilute  solution  of  potash  is  not  a  property  exclusively  belonging 
to  Yolckel's  creosote. 
The  result  of  the  author's  analyses  of  creosote,  treated  with 
potash  according  to  Yolckel's  directions,  come  very  near  the 
average  of  the  analyses  of  creosote  not  treated  with  potash. 
The  author  then  compares  the  formulae  to  which  the  previous 
investigations  of  creosote  have  led.  The  formuhe  are  C26  H16  O4, 
C24  Hi5  04?  and  yolckel's  C24  II14  O5 ;  and  he  is  of  opinion  that 
