AmSep°t"r*i9ih£rm")     Determination  of  Methyl  Alcohol.  639 
Burettes  as  produced  for  other  operations  need  correction  in  one 
particular.  Unless  one  end  is  corked,  gas  would  pass  through  it. 
Therefore,  secure  a  sound  well-fitting  cork  which  push  into  the 
burettes  with  a  rod,  until  it  registers  at  zero  and  forms  the  roof  of 
the  collecting  cylinder  when  in  operation. 
Operation. — The  gas  in  this  case,  like  all  others,  is  collected 
over  a  fluid.  In  this  instance,  however,  certain  precautions  must  be 
observed.  We  are  working  with  the  highly  oxidizable  metal  sodium, 
this  forbids  any  watery  liquid,  in  addition  to  the  other  fact  that  our 
alcohol  must  be  anhydrous.  This  suggests  then  a  hydrocarbon  oil 
as  the  most  appropriate  liquid.  For  the  sake  of  cleanliness  and 
rapid  action,  the  oil  should  have  the  lowest  viscosity.  Therefore, 
our  choice  fell  upon  ordinary  gasoline  as  meeting  the  conditions  best 
of  all. 
Both  hydrometer  jars  are  filled  to  a  convenient  depth  with  gas- 
oline. Into  one  of  the  small  test-tubes  drop  from  a  pipette  six  drops 
of  the  prepared  standard  alcohol  previously  dehydrated.  Cork  it  at 
once  as  previously  described.  Submerge  it  in  the  gasoline  contained 
in  one  of  the  hydrometer  jars.  Now  fill  one  of  the  burettes  with 
gasoline,  close  it  with  the  operator's  thumb,  be  sure  there  is  no  bubble 
of  air.  invert  the  burette  and  place  the  end  beneath  the  gasoline  in 
the  hydrometer  jar,  remove  the  thumb  and  carefully  guide  the 
burette,  containing  its  column  of  gasoline  intact,  over  the  trap  and 
down  over  the  brass  tube.  When  it  encounters  the  spring  clip,  the 
silk  thread  is  released,  the  needle  bearing  the  sodium  drops  into  the 
alcohol.  The  reaction  begins  at  once,  and  the  hydrogen  forces  its 
way  out  through  the  trap,  is  collected  in  the  burette  where  it  is  read 
in  cubic  centimeters  and  fractions  thereof. 
The  unknown  alcohol  is  treated  in  precisely  the  same  way,  using 
the  same  number  of  drops  and  from  the  same  pipette. 
If  the  reading  of  the  unknown  sample  is  less  than  that  of  the 
standard  it  is  deficient  in  wood  alcohol.  If  greater,  the  wood  alcohol 
is  in  excess  of  the  requirement.  If  the  two  operations  are  conducted 
side  by  side,  all  considerations  of  temperature,  barometric  pressure, 
etc.,  may  be  ignored  as  they  are  identical  in  each  instance. 
Dr.  Charles  A.  Crampton,  a  former  Chief  Chemist  of  the  In- 
ternal Revenue  department,  after  witnessing  a  demonstration  of 
this  method  and  apparatus,  appeared  at  a  hearing  before  the  Ways 
and  Means  Committee  and  testified  that  "There  is  in  existence  a 
simple  method  and  apparatus  that  is  capable  of  proving  denatured 
