HYDRIDE    OF  AMYLE. 
419 
proved  to  be  the  pure  radical,  and  which  had  now  been  got  in  a 
separate  form  for  the  first  time.  This  liquid  is  colorless  and 
clear,  of  a  density  of  .770,  and  boils  at  155°  C,  or  311°  F.,  and 
the  density  of  its  vapor  is  4.9. 
As  Dr,  Frankland  found,  in  his  previous  investigations  for  the 
discovery  of  the  radical  of  wine  alcohol,  that  on  exposing  the 
iodide  of  ethyle  with  an  equal  bulk  of  water  along  with  zinc  in 
sealed  tubes  to  the  action  of  heat,  the  only  product  was  the  hy- 
dride of  ethyle,  he  was  led  to  try  the  same  process  with  the  iodide 
of  amyle,  and  the  result  of  the  use  of  water  in  the  reaction  was 
exactly  analogous.  Instead  of  a  mixture  of  amylene,  amyle  and 
its  hydride,  he  now  obtained  as  the  only  product  of  decomposi- 
tion the  hydride  of  amyle,  which  distilled  off  at  a  very  low  heat, 
and  after  digesting  the  liquid  for  twenty-four  hours  with  caustic 
potash,  and  redistilling  at  35°  0.,  or  95°  F.,  was  obtained  quite 
pure. 
He  also  found,  that  by  the  addition  of  water  to  the  iodide  and 
zinc,  the  decomposition  easily  took  place  at  a  heat  of  140°  C, 
or  285°  F.,  whilst  with  the  iodide  and  zinc  alone  a  heat  of 
1909  C.  was  required,  besides  the  necessity  of  amalgamating  the 
zinc. 
On  proceeding  to  prepare  the  hydride  for  Dr.  Simpson,  we 
very  soon  discovered  the  unsuitableness  of  sealed  tubes,  as  used 
by  Dr.  Frankland,  for  its  preparation  in  sufficient  quantity  to 
test  its  powers  as  an  anaesthetic.  We  therefore  got  much  larger 
tubes  made,  and  carefully  annealed,  of  one  inch  internal  diame- 
ter, and  I  of  an  inch  thick  ;  and  instead  of  being  sealed,  which 
necessarily  involved  their  destruction  at  each  operation,  we  had 
them  effectually  closed  by  accurately  ground  stoppers,  and  these 
again  strongly  fixed  down  in  their  places  by  a  metal  bridle,  with 
a  binding  screw.  But  from  the  enormous  pressure,  not  less  than 
300  lbs.,  or  twenty  atmospheres,  by  calculation,  to  the  inch,  there 
was  extreme  difficulty  in  getting  the  stoppers  perfectly  tight. 
Seeing,  however,  superior  advantages  in  this  plan  over  the  other, 
if  the  stopper  could  be  made  tight,  we  were  induced  to  persevere, 
and  at  length,  with  great  care  in  the  grinding,  succeeded  in 
making  an  absolutely  tight  tube,  even  under  such  great  pressure. 
But  from  the  great  risk  of  explosion  with  such  size  tubes,  we 
afterwards  gave  up  the  idea  of  glass  ones  altogether.    One  of 
