148  Acetone  and  Acetone-Chloroform.  {.^itoStiSSf^ 
tions  of  the  mass  will  be  subjected  to  the  heat  resulting  from  direct 
contact  with  the  bottom  of  the  vessel,  and  by  admitting  free  steam 
from  time  to  time  into  direct  contact  with  the  acetates  in  case  of 
any  undesirable  rise  in  temperature  within  the  vessel. 
"  My  invention  consists  in  an  improvement  in  the  method  of  ob- 
taining acetone  from  acetates  by  destructive  distillation,  consisting 
in  subjecting  the  acetates  in  a  closed  vessel  to  slow  destructive  dis- 
tillation at  a  low  and  approximately  uniform  temperature,  and  it  is 
also  well  to  stir  the  acetates  during  such  distillation." 
The  claims  are  to — 
"  The  improvement  in  the  method  of  obtaining  acetone  from  an 
acetate,  consisting  in  subjecting  the  acetate  in  a  closed  vessel  to  slow 
destructive  distillation  at  a  low  and  approximately  uniform  temper- 
ature." 
This  first  broad  claim  is  based,  not  upon  the  chemical  reaction, 
which  was  well  known,  nor  upon  the  destructive  distillation  by  heat, 
which  was  a  well-known  process,  but  upon  an  improvement  in  the 
apparatus  and  management,  by  which  the  yield  of  acetone  was 
alleged  to  have  been  increased.  But  the  evidence  upon  which  the 
increase  is  claimed  is  an  erroneous  statement  quoted  from  Hager — 
erroneous  because  it  is  hardly  practicable,  through  any  ordinary  de- 
gree of  want  of  knowledge  and  skill,  to  obtain  so  little  as  15  per 
cent,  of  acetone  from  acetate  of  lime. 
The  second  claim  is  to  a  stirrer  in  its  effects  on  the  process.  But 
a  stirrer  is  a  device  so  common  in  chemical  processes  that  no  such 
application  of  it  can  be  considered  original  or  new. 
The  third  claim  to  the  effect  of  the  introduction  of  steam  during 
the  distillation  is  much  better. 
The  fifth,  sixth,  seventh  and  eighth  claims  are  to  improvement  in 
the  process  of  purifying  the  crude  acetone  by  means  of  lime,  dilu- 
tion and  rectification,  and  these  are  but  the  steps  common  to  all  such 
operations. 
It  is  upon  this  patent  that  infringement  is  charged,  when  it  is 
simply  putting  into  use  the  very  old  process  of  making  acetone  by 
the  destructive  distillation  of  acetic  acid  in  a  rotary  still,  as  described 
in  a  paper  on  "  Improvement  in  the  Manufacture  of  Acetone,"  read 
before  this  New  York  Section  of  The  American  Chemical  Society, 
on  January  n,  1895,  and  published  in  The  Journal  of  the  American 
Chemical  Society  for  March,  1895,  P-  ^7,  and  in  An  Ephemeris  of 
