35©  Mr.  Milner  on  the  Communication  of 
fhall  both  underhand  the  fubject  better  than  we  did  be-* 
fore,  and.be  more  on  our  guard  for  the  future.. 
The  firft  law  of  motion,  as  exprefled  by  Sir  Isaac 
newton,,  is  unexceptionable : nobody  denies  that  a body 
perfeveres  in  a hate  of  reft  or  uniform  motion  in  a right 
line,  till  affected  by  fome  external  influence.  It  is  the 
third  law  of  motion,  which  has  produced  all  this  confu- 
flon  and  perplexity,.  w Adtioni  contrariam  femper  et 
s(  sequalem  efle  readtionem : .five  corporum  duo  rum  ac- 
“ tiones  in  fe  mutuo  femper  aequales  et  in  partes  con- 
trarias  dirigi.”  Thefe  words  of  Sir  isaac  newton 
convey  to  us  as  clear  an  idea  as  can  poflibly  be  conceived 
with  fo  much  concifenefs.  It  muft  however  be  confeffed,.. 
that  his  ill  nitration  is  not  fo  very  perfpicuous (b> . To  fay,, 
that  when  a man  preffes  a ftone  with  his  finger,  his  fin- 
ger is  equally  prefled ;.  and,  when  a liorfe  draws  a ftone 
by  a cord,  the  horfe  is  drawn  equally  backwards- towards 
the  ftone;  is  a moft  indiftin<St  and  popular  way  of  fpeak- 
ing,  and  can  never  make  evident  what  was  before  not 
underftood. 
(b)  Quicquid  premit  vel  traliit  alterum,  tantundcm  ab  eo  premitur  vePtra* 
hitur.  Si  quis  lapidem  digito  premif, .premitur  et  hujbis-digitus  a lapide.  Si 
cquus  lapidem  funi  alligatum  trahit,  retrahitur -etiatn  et  equus  (ut  ita  dicam) 
sequaliter  in  lapidem:  nam  funis  utrinque  diftentus  eodem  relaxandi  fe  conatu 
urgebit,  equum  verfus  lapidem,  ac  lapidem  verfus  equum;  tantumque  impediet 
progreifum  uni  us  quantum  promo  vet  progreffum  alterius,  &c.  newton  Princip. 
Some 
