346  ATr.  milner  on  the  Communication  of 
is  juftly  dtie  to  the  incomparable  Galileo.  The  theory 
of  mechanics  had  received  no  confiderable  improvement 
lince  the  time  of  Archimedes,  when  this  furprizing  ge- 
nius appeared  in  the  former  part  of  the  feventeenth  cen- 
tury. He  difcarded  the  peripatetic  philofophy ; explained 
the  whole  doctrine  of  accelerated  motion  and  of  projec- 
tiles : in  a word,  he  fo  much  exhaufted  the  fubject,  that 
the  belt  treatifes  we  have  at  this  day  are  little  more  than 
a repetition  of  Galileo’s  difcoveries. 
This  philofopher,  as  far  as  we  know,  never  attempted 
to  inveftigate  the  laws  by  which  motion  is  communi- 
cated from  one  body  to  another.  The  celebrated  des 
cartes  is  the  firft  we  hear  of  who  gave  any  attention  to 
the  fubjedt;  and  the  refult  of  his  enquiries  is  what  might 
reafonably  be  expected  from  fo  whimiical  and  romantic 
a genius;  he  blundered  in  this,  as  in  all  other  cafes, 
where  he  was  not  confined  to  pure  mathematical  rea- 
fonings.  Our  countryman,  Dr.  wallis,  made  a real  pro- 
grefs  in  this  fcience,  by  difcoveririg  that  fundamental  law 
in  the  communication  of  motion,  viz.  that  adtion  is  equal 
tore-action,  and  always  in  contrary  directions:  wren, 
Huygens,  confirmed  the  fame  thing;  and  the  whole 
theory  of  the  collifion  of  bodies,  and  their  mutual  actions 
upon  one  another,  feemed  to  be  advancing  faft  towards 
perfection. 
But 
