from  Lightning  at  Purfleet.  297 
in  the  thirty-eighth  experiment,  where  the  long  wire 
was  employed,  was  coniiderably  greater  than  when  the 
great  cylinder  alone  was  charged,  we  feem  to  have  fuf- 
ficient  reafon  to  apprehend  that  the  effects  of  every 
charge,  as  to  fenfation,  willbe  proportional  to  the  length 
of  the  body  charged  ; provided  the  charge  (or  accumula- 
tion) be  uniform  from  end  to  end  in  every  experiment. 
Apprehending  that,  if  fome  of  the  circumftances  em- 
ployed in  producing  the  charge  were  varied,  we  might 
poffibly  obtain  a greater  charge  than  we  had  yet  found, 
I made  the  following  experiments. 
exp.  xliv.  Inftead  of  one  machine  to  charge  the 
great  apparatus  I made  ufe  of  two.  The  glafs  cylinders 
belonging  to  each  were  of  the  fame  length  and  diameter 
nearly.  One  of  thofe  machines  was  continued  in  its 
ufual  place,  which  was  not  far  from  the  nearer  end  of 
the  great  cylinder.  The  other  flood  at  the  farther  end  of 
the  brafs  drums.  After  connecting  the  long  wire  with 
the  great  cylinder  and  brafs  drums,  in  the  manner  before 
defcribed,  the  wheels  of  both  machines  were  put  into 
motion,  with  equal  and  uniform  velocities:  and  after 
iix  turns  of  each  wheel  (for  I could  not  prevail  upon 
any  one  prefent  at  the  time  to  take  a higher  charge), 
and,  after  waiting  above  eight  feconds,  a perfon  fud- 
denly 
