398 
ON  KEROSOLENE. 
the  ordinary  coal  tar  products  in  considerable  proportion.  The 
light  naphtha  first  obtained  in  the  distillation  of  coal  tar  has  a 
sp.  gr.,  according  to  Mansfield,  of  -900  to  -950,  and  when  puri- 
fied by  agitation  with  sulphuric  acid  and  potash,  or  by  the  pro- 
cess of  Gregory,  in  which  peroxide  of  manganese  is  used,  and 
rectified,  its  density  does  not  fall  below  that  of  benzine,  the  sp. 
gr.  of  which,  in  its  liquid  form,  is  variously  stated  at  -85  and 
•8991,  at  different  temperatures. 
The  largest  proportion  of  Kerosolene  is  evidently  composed  of 
those  very  light  carbohydrogens  not  present  in  coal  tar,  and 
not  produced  at  the  high  temperatures  employed  in  the  produc- 
tion of  illuminating  gas. 
In  the  books  I  have  consulted  I  find  no  detailed  account  of 
these  almost  gaseous  liquids,  and  T  can  imagine  no  subject  pre- 
senting more  difiBculties  to  the  chemist.  Prof.  Antisell,  in  his 
thoroughly  practical  work  on  Photogenic  and  Hydrocarbon  Oils, 
remarks  that  "  the  specific  gravity  and  chemical  constitution  of 
the  light  and  heavy  oils  vary  in  relation  to  the  temperature  at 
which  they  are  distilled  ;  and  perhaps  no  two  distillations  give 
exactly  the  same  relative  mixture  of  the  various  hydrocarbons 
of  which  they  are  composed."  The  composition  of  these  is 
further  varied  by  the  nature  of  the  crude  materials,  which  may 
be  highly  bituminous  like  the  "Albert  coal,"  from  which  the 
specimens  under  consideration  were  obtained,  or  more  completely 
formed  coals  like  the  more  common  varieties. 
The  proportion  of  matter  volatile  ai  redness  in  the  ^'Albert 
coal"  has  been  stated  at  61-74  per  cent.,  that  of  the  "Breck- 
enridge  coal,"  of  Kentucky  at  60-27  per  cent.,  while  Pittsburg 
coal  yields  but  32-95  per  cent. 
Chemists  have  obtained  from  coal  tar  by  fractional  distillation 
several  substances  of  great  utility.  Of  these,  benzine  or  benzole 
Ci2H^,  which,  as  before  stated,  is  the  chief  constituent'  of 
the  liojht  naphtha,  is  also  a  constituent  of  kerosolene,  as  ascer- 
tained by  testing  it  with  nitric  acid,  which  developed  the  odor 
of  nitrobenzole.  The  chief  constituents  of  the  photogenic 
liquids  as  thrown  into  commerce  under  the  name  of  Coal  oils  or 
kerosolene,  are  Toluine  C^^Hg,  which  has  asp.  gr.  of  -870  and 
boiling  point  237"^  F.,  (Gerhardt  -230,)  and  Cumene  C^qRi2i 
which  is  also  lighter  than  water,  and  boils  at  -314°;  it  is  not  im- 
