412 
CHEMICAL  RESEARCHES  ON  AMYLENE. 
showing  its  adulterations.  But  most  specially  should  pharma- 
ceutists and  chemists  bestir  themselves  with  a  view  of  furnishing 
a  good  preparation  at  the  lowest  possible  price. 
Apparatus  The  material  composing  the  apparatus  is  a  sub- 
ject worthy  of  consideration.  Glass  retorts  are  generally  used 
when  active  reagents  are  required  ;  and  in  this  view  the  chloride 
of  zinc  would  appear  to  demand  their  employment,  there  being 
no  chemical  action  thereby  produced  on  the  glass,  and  its  trans- 
parency permitting  ready  observation.  Amylene,  up  to  the  pre- 
sent time,  has  generally  been  prepared  by  means  of  glass  vessels. 
I  myself  used  them  in  my  first  trials,  but  I  soon  realized  their 
insufficiency  and  inconvenience.  They  are  not  adapted  to  an 
extensive  production  of  amylene  ;  they  required  a  great  deal  of 
combustible  material,  and  from  their  fragility,  they  expose  the 
manipulator  to  the  occurrence  of  serious  acidents.  A  distillation 
from  glass  is  tedious  and  difficult,  even  when  we  take  the  great- 
est care  to  cover  the  arch  of  the  retort  in  the  most  careful  manner 
in  the  sand-bath,  in  order  to  retain  the  heat.  If  amylene  were 
produced  at  a  low  temperature,  and  if  it  passed  alone  into  the 
receiver  in  distillation,  these  inconveniencies  would  not  exist ; 
but  as  it  comes  over  at  first  with  its  congeners,  paramylene  and 
metamylene,  these  heavy  vapors  when  at  the  summit  of  the  re- 
tort, give  out  their  latent  heat,  and  they  become  condensed,  and, 
for  the  most  part,  descend  again.  Meanwhile  the  chloride  of 
zinc  becomes  concentrated,  abandons  a  part  of  its  water,  and  be- 
comes more  and  more  active,  and  it  then  carbonizes  a  part  of 
the  amylic  alcohol  and  of  the  hydro-carburets,  and  at  the  same 
time  this  radical  alteration  imparts  to  the  amylene  a  strong  em- 
pyreumatic  odor.  I  therefore  now  make  use  of  a  copper  alembic, 
this  metal  not  being  acted  on  by  the  chloride  of  zinc.  In  this 
apparatus,  which  is  indeed  required  in  every  laboratory,  the 
process  is  conducted,  at  a  less  expense,  and  by  its  use  we  make 
a  considerable  step  towards  the  reduction  of  the  price  of  amylene. 
PRELIMINARY  EXPERIMENTS. 
The  action  of  the  Chloride  of  Zinc,  at  different  degrees  of  tern 
perature,  on  Amylic  Alcohol. — I.  When  potato-oil  is  agitated  with 
the  chloride  of  zinc  coarsely  broken,  the  mixture  becomes  a  little 
heated,  and  on  reposing,  the  saturated  oil  being  separated  from 
the  excess  of  the  salt,  and  mixed  with  a  certain  proportion  of 
