128        Herbert  Spencer  and  the  Metric  System.  {AmMi?^;f^f.rm* 
"  Evidently  moved  by  the  desire  for  human  welfare  at  large,  scien- 
tific men  have  been  of  late  years  urging  that  the  metric  system 
should  be  made  universal,  in  the  belief  that  immense  advantages, 
like  those  which  they  themselves  find,  will  be  found  by  all  who  are 
engaged  in  trade.  Here  comes  in  the  error.  They  have  identified 
two  quite  different  requirements.  For  what  purpose  does  the  man  of 
science  use  the  metric  system  ?  For  processes  of  measurement.  For 
what  purpose  is  the  trader  to  use  it  ?  For  processes  of  measurement, 
plus  processes  of  exchange.  This  additional  element  alters  the  prob- 
lem essentially.  It  matters  not  to  a  chemist  whether  the  volumes  he 
specifies  in  cubic  centimetres,  or  the  weights  he  gives  in  grammes 
are,  or  are  not,  easily  divisible  with  exactness.  Whether  the  quan- 
ties  of  liquids  or  gases  which  the  physicist  states  in  litres  can  or 
can  not  be  readily  divided  into  aliquot  parts  is  indifferent.  And  to 
the  morphologist  or  microscopist,  who  writes  down  dimensions  in 
subdivisions  of  the  metre,  the  easy  divisibility  of  the  lengths  he  states, 
is  utterly  irrelevant.  But  it  is  far  otherwise  with  the  man  who  all 
day  long  has  to  portion  out  commodities  to  customers  and  receive 
money  in  return.  To  satisfy  the  various  wants  of  those  multitudes 
whose  purchases  are  in  small  quantities,  he  needs  measures  that 
fall  into  easy  divisions,  and  coinage  which  facilitates  calculation  and 
the  giving  of  change.  Force  him  to  do  his  business  in  tenths,  and 
he  will  inevitably  be  impeded." 
Finally,  it  may  be  said  that  Spencer  was  well  aware  of  the  advan- 
tage to  be  derived  from  the  application  of  the  decimal  method  o  f 
calculation  to  quantities  and  values;  that  he  was  in  favor  of  a  uni- 
form system  of  weights  and  measures,  but  held  that  this  was  no 
possible  with  the  metric  system,  believing  that  it  would  necessarily 
be  traversed  by  other  systems,  and,  notwithstanding  the  difficulties 
which  would  oppose  the  introduction  of  a  duodecimal  system,  he 
believed  that  its  merits  were  such  as  to  warrant  the  use  of  our  pres- 
ent mixed  system  until  such  time  as  this  more  perfect  system  could 
be  adopted. 
