Mr.  milner  on  the  Communication , See.  345 
This  laft  circumftance  induced  fome  of  the  philofophers 
we  are  fpeaking  of  to  believe,  that  a cannon  ball,  for  in- 
ftance,  always  moves  in  the  fame  ft  r ait  line  till  its  velo- 
city is  entirely  deftroyed ; and  that  afterwards  it  defeends 
towards  the  earth  in  a direction  perpendicular  to  the  ho- 
rizon. Others  thought  they  mended  the  matter  by  fuf- 
pending  the  aCtion  of  gravity  for  a certain  period  only ; 
by  allowing  the  latter  part  of  the  path  to  be  curvilinear ; 
and  laftly,  the  body  to  defeend  to  the  earth  in  a ftraight 
line,  as  in  the  former  cafe.  We,  in  thefe  days,  who  have 
feen  the  gradual  improvements  in  mechanics  from  time 
to  time,  are  not  furprized,  that  men,  in  the  infancy  of 
that  fcience,  fhould  have  embraced  abfurd  and  ridiculous 
principles:  we  rather  wonder,  how  the  author (a>  of  the 
notion  juft  mentioned  was  able  to  form  any  juft  eftimate 
of  the  horizontal  ranges  of  projectiles,  and  to  difeover 
their  maxima.  Whether  by  conjecture,  or  probability 
of  induction,  we  are  unable  to  determine  ; but  fo  it  was, 
tartalea  affirmed,  what  has  fince  been  found  true  upon 
unexceptionable  evidence,  that  the  amplitudes  of  pro- 
jectiles upon  the  horizon  are  always  greateft  when  the 
angles  of  projection  are  equal  to  450.  But  the  praife  of 
this  difeovery,  as  well  as  whatever  elfe  relates  to  the  ac- 
celerated motions  of  bodies  near  the  furface  of  the  earth, 
(a)  NICH.  tartalea. 
is 
