6l2 
Chemical  Notes. 
\ni    Jour.  Pharn^. 
Dec,  1880. 
anthracene,  Cj^Hjo,  chrysene,  C^gHigand  picene,  C^^H^^. — Ber.der  Chem. 
Ges.^  xiii,  p.  1834. 
On  the  Nature  of  Caucasian  Petroleum. — The  Russian  chemists  Beil^ 
stein  and  Kurbatow  have  made  a  chemical  study  of  the  petroleum  now 
produced  in  such  large  amounts  in  the  Caucasus.  It  had  been  observed 
that  the  Russian  oils  of  the  same  boiling  point  as  American  petroleums 
had  a  much  higher  specific  gravity,  and  that  so  far  from  this  impairing 
their  burning  qualities,  they  yield  a  light-giving  power  10  per  cent,  higher 
than  the  American  oils.  This  higher'specific  gravity,  moreover,  made 
it  possible  to  obtain  from  the  Russian  oils  lubricating  oils  of  the  best 
quality  (even  up  to  0*940  specific  gravity)  without  the  admixture  of 
any  solid  materials.  The  Russian  chemists  directed  their  study 
especially  to  the  more  volatile  portions  of  the  crude  oil.  Thus  the 
fraction  boiling  under  8o°C.  was  found  to  have  a  specific  gravity  of  07 1 7, 
while  hexane,  the  paraffin  hydrocarbon  of  the  same  boiling  point,  has 
a  specific  gravity  of  0'669  ;  the  fraction  between  95  to  ioo°C.  had  a 
specific  gravity  of  0*748,  while  heptane  has  a  specific  gravity  of  '699. 
The  first  supposition  of  the  investigators  was  that  the  Russian  oils 
were  mixtures  of  the  paraffin  series  and  the  aromatic  or  benzol  series. 
However,  they  could  not  find  a  trace  of  the  benzol  series  in  any  of 
the  fractions.  An  analysis  of  the  80  to  85°C.  fraction  gave  results 
corresponding,  not  with  the  formula  Q^Yi.f^^  but  C^Hj^.  The  hydro- 
carbons of  the  Russian  oil  are  not,  however,  members  of  the  olefine 
series,  Cj^Hg^,  as  bromine  has  no  action  upon  them,  except  in  the  way 
of  substitution.  They  are  the^  hydrogen  addition  products  of  the  ben- 
zol series  of  hydrocarbons.     Wreden  had  studied  these  and  found  for 
Hexahydrobenzol,  CgH,^  0.76  sp.  gr.  69*^0.  boiling  point.. 
Hexahydrotoluol,  ^i^n  0772  97^C. 
Hexahydroisoxylol,  CgHjg  o'777  ii8°C. 
Beilstein  and  Kurbatow  substantiated  this  view  of  the  composition  of 
the  oil  by  preparing  derivatives  like  trinitroisoxylol,  identical  with  that 
prepared  from  metaxylol  of  coal  tar.  Farther  observations  upon  these 
Caucasian  oils  are  promised. — Ibid.^  p.  18  18. 
Differences  between  Petroleum  Spirit  and  Allied  Liquids. — A.  H.  Allen,, 
in  a  paper  read  before  the  British  Association  at  Swansea,  1880,  sums 
up  the  differences  between  petroleum  spirit,  shale  naphtha  and  coal- 
tar  naphtha,  as  follows: 
