XWM™Xw?M'}         Paraffin  in  Stearin  Candles.  127 
suggestion  of  several  professional  friends.  Any  chemist  can  easily 
construct  the  apparatus,  or  it  may  be  purchased  of  dealers  in  chemi. 
eal  apparatus. — Amer.  Chemist,  Dec.,  1872. 
DETECTION  AND  ESTIMATION  OF  PARAFFIN  IN  STEARIN 
CANDLES. 
By   M .  Hock. 
Makers  of  stearin  candles  mix  paraffin  with  the  fatty  mass  in  quan- 
tities up  to  20  per  cent.  Paraffin  candle  makers  also  mix  stearic  acid 
"with  their  paraffin,  and  attribute  valuable  properties  to  such  a  mixture, 
so  far  as  candle-making  is  concerned.  The  attempt  to  determine  if 
paraffin  be  present,  and  if  so,  to  get  some  approximate  idea  of  the 
quantity,  in  a  sample  of  stearin  and  vice  versa,  by  means  of  the  com- 
parison of  the  melting-point  and  specific  gravity  of  such  a  mixture, 
is  shown  to  be  useless,  as  these  vary  according  to  the  source  from 
which  the  paraffin  is  obtained,  as  also  in  the  case  of  the  stearic  acid, 
since  the  pure  commercial  article  is  by  no  means  a  chemically  pure 
article. 
A  good  method  of  detecting  the  presence  of  stearic  acid  in  paraffin 
lias  been  devised  by  R.  Wagner,  viz.,  by  treating  a  boiling  solution 
of  the  paraffin  in  alcohol  with  an  alcoholic  solution  of  neutral  acetate 
©f  lead,  when,  if  stearic  acid  be  present,  a  dense  floccular  precipitate 
appears,  but  none  if  it  be  absent.  The  best  method,  and  one  which 
can.  be  used  quantitatively  as  well  as  qualitatively,  is  described  as 
follows : 
Not  less  than  5  grms.  of  the  candle  are  taken  and  treated  with 
warm  solution  of  hydrate  of  potash,  which  must  not  be  too  concen- 
trated. A  soap  is  formed  with  the  stearic  acid,  whilst  the  paraffin  is 
left  unaltered.  Salt  is  thrown  into  the  solution,  whereby  the  soap  is 
separated  out  as  a  soda  soap,  and  in  precipitating  takes  down  the  pa- 
raffin with  it.  The  soap  obtained  is  thrown  on  the  filter  and  washed 
with  cold  water  or  very  dilute  spirits  of  wine.  Thus,  firstly,  the  salt 
is  washed  out,  and,  finally,  the  soap  is  brought  into  solution  and  like- 
wise washed  through  the  filter,  leaving  the  paraffin,  which  is  then 
dried  at  a  temperature  below  35°  C,  so  as  not  to  fuse  it.  The  pa- 
raffin is  then  treated  on  the  filter  with  ether,  and  after  repeated  wash- 
ing with  this  solvent,  the  ethereal  solution  is  carefully  evaporated  in 
at  weighed  porcelain  crucible,  in  the  water-bath,  at  a  low  temperature. 
