638  Determination  of  Methyl  Alcohol.     {Am-sJp0tur- J^™' 
observations  upon  a  known,  previously  prepared  standard  denatured 
alcohol;  fifth,  to  conduct  the  same  experiments  upon  an  equal  vol- 
ume of  the  alcohol  to  be  tested,  and  to  compare  the  result  of  the 
unknown  with  that  of  the  known  standard. 
To  successfully  prosecute  this  plan,  we  found  it  necessary  to 
provide  two  hydrometer  jars  of  at  least  1,000  Cc.  capacity,  two 
50  Cc.  graduated  burettes  graduated  in  %0  Cc,  two  small  test-tubes 
on  foot. 
The  remainder  of  the  apparatus,  which  is  simple,  was  required 
to  be  originated  and  produced  by  us,  as  follows :  two  perfect  corks 
to  fit  the  small  test-tubes  on  foot,  two  10-inch  lengths  of  ^g-inch 
thin  wall,  brass  tubing.  Perforate  the  corks  and  insert  one  end  of 
each  brass  tube  into  the  cork  perforated  for  it.  Pass  the  brass  tub- 
ing entirely  through  the  cork  until  its  end  comes  even  with  the  cork 
surface,  make  a  tight  joint  by  sealing  with  hot  fused  shellac  or  seal- 
ing wax;  upon  the  opposite  end  of  each  of  the  brass  tubes  mount  a 
trap  that  will  permit  gas  to  escape,  but  prevent  liquid  from  entering 
— and  be  sure  that  the  trap  is  not  too  large  in  diameter  to  enter  the 
bore  of  the  graduated  burette. 
If  now  the  test-tubes  are  corked  with  the  tubes  as  described  they 
may  be  submerged  in  liquid  without  risk  of  any  of  the  liquid  passing 
into  the  interior — whereas,  any  gas  generated  within  the  test  tubes 
could  readily  force  passage  through  the  brass  tube  and  out  through 
the  trap  surmounting  it,  to  be  finally  collected  for  measurement  in 
the  burette,  inverted  over  all. 
These  are  the  main  requirements,  but  to  operate  them  accurately 
it  was  also  found  necessary  to  provide  further  a  weight  secured  to 
the  foot  of  the  test-tube  to  sink  and  stabilize  it  in  the  liquid  when 
submerged.  Also  we  adopted  as  a  means  for  introducing  the  metallic 
sodium,  a  large  darning  needle  with  an  eye  through  which  passed  a 
length  of  sewing  silk.  The  silk  passed  through  the  brass  tube  out 
through  the  trap — down  along  the  outside  of  the  brass  tube  where 
it  was  secured  near  the  cork  by  a  spring  clip,  so  arranged  that  it  re- 
leased the  thread  when  the  burette  was  inverted  over  all  and  pressed 
down  ready  for  a  reading. 
The  releasing  of  the  thread  permitted  the  needle  to  fall  into  the 
test  tube  which  contained  the  alcohol  to  be  tested.  The  pointed  end 
of  the  needle  carried  a  piece  of  metallic  sodium  in  large  excess.  The 
needle  was  weighted  to  insure  prompt  action.  By  this  arrangement 
no  action  occurred  until  everything  was  set  and  ready  for  it. 
