Even  when  it  is  used,  not  to  test  thinking,  but  merely  to  elicit
fresh  information,  it  is  still  an  outcome  of  deduction ;  for  it  is  de-
duction which  leads  us  to  suppose  that  our  experiment  will  have
useful  results.  It  follows  that  there  are  two  ways  in  which  we
may  use  experiment  (or  any  other  laboratory  method).  First  we
may  use  it  as  a  deductive  test  of  previous  thinking,  in  which  it
tends  to  secure  great  accuracy  in  thinking.  Second,  we  may  use
it  as  a  means  to  reveal  an  obscured  fact,  when,  of  course,  it  tends
to  secure  accuracy  in  observing.  But,  in  the  latter  case,  if  we  base

1  Welton,  Manual  of  Logic,  vol.  ii.  p.  66.  2  Op.  cit.,  vol.  ii.  p.  88.
