Velocities  of  Cannon  Balls , See.  7 3 
1 to  1. 414;  that  is,  accurately  the  ratio  of  the  fquare 
roots  of  the  quantities  of  powder. 
Of  the  experiments  made  with  the  other  pendulum , which' 
is  reprefented  in  Jig.  1. 
The  firft  pendulum  was  gradually  more  and  more 
rent  and  fhattered  by  the  firing  of  fo  many  balls  into  it, 
till  at  the  end  of  the  laffc  courfe  of  experiments  it  had 
become  quite  ufelefs.  Another  was  then  fitted  up,  and 
with  it  were  performed  the  two  following  courfes. 
This  fecond  pendulum  confifted  Of  a cubical  block 
of  found  elm,  of  near  two  feet  long,  fixed  to  the  iron 
item,  but  not  exactly  in  the  manner  of  the  former;  for 
in  this  the  ftem  was  placed  vertically  over  the  center  of 
the  top-end,  to  which  point  it  continued  whole,  but 
there  divided  in  two,  each  paffing  to  right  and  left  over 
the  top  down  the  fides,  and  returning  along  the  bottom, 
and  being  at  proper  intervals  fattened  to  the  wood  with 
iron  pins.  A thick  ftieet  of  lead  was  fattened  over  each 
of  the  two  upright  faces  into  which  the  fliot  were  to  be 
fired,  both  to  guard  them  from  fplintering  very  much, 
and  to  add  to  the  weight  of  the  pendulum.  The  whole 
was  tfcen  firmly  fecured  by  two  very  thick  iron  bands  or 
hoops,  patted  horizontally  quite  around  the  wood,  and 
Vol.  LXVIII.  L firmly 
