348  Mr.  milner  on  the  Communication  of 
it  is  a ferious  perfuafion,  that  the  laws  by  which  motion 
is  communicated  are  ftiil  very  materially  miftaken  by 
fenfible  perfons,  that  induced  me  to  throw  together  the 
following  hints,  and  to  lay  them  before  the  Royal  So- 
ciety. The  right  underftanding  of  thefe  laws  is  of  the 
laft  importance  in  practice : the  good  or  bad  fuccefs  of 
fome  very  cxpenfive  projects  has  depended  upon  it;  and 
certain  excellent  artifts  have  been  difappointed  in  the 
execution  of  their  plans,  and  unable  to  reconcile  the  ap- 
parent contradiction  between  theory  and  experiment. 
From  the  length  of  time,  which  has  elapfed  fince  Leib- 
nitz.firft  advanced  his  new  opinions,  and  tlxe  abilities  of 
the  philofophers  who  engaged  in  the  conteft,  one  might 
have  expected,  that  the  whole  matter  would  long  before 
this  have  been  cleared  up  in  a fatisfaCtory  manner;  efpe- 
cially  when  we  confider,  that  the  communication  of  mo- 
tion from  one  body  to  another  is  what  every  moment 
happens  before  our  eyes,  and  that  particular  experiments 
are  made  in  this  doCtrine  with  the  greateft  limplicity  and 
convenience.  This  part  of  rational  mechanics  however 
is  not  yet  generally  underftood,  as  wre  may  fairly  pre- 
fume from  the  difference  of  opinion  which  ftiil  fubfifls 
among  the  learned.  I freely  own,  it  appears  to  me,  that 
no  new  experiments  are  wanting;  no  new  geometrical 
reafonings  or  conftruCtions ; the  improved  parts  of  geo- 
metry 
