from  Lightning  at  Pur  fleet.  267 
lee  what  effect  the  charge  itfelf  has  upon  the  model, 
without  any  conductor  upon  it. 
exp.  xvi.  Upon  charging  the  great  cylinder  as  before, 
that  is,  by  twenty  turns  of  the  wheel,  and  when  the 
model,  without  any  conductor  upon  it,  was  let  go,  there 
was  no  explofion  in,  or  on,  any  part  of  it,  during  the  time 
of  its  palling  by  the  cylinder;  notwithftanding  the  model 
itfelf  was  properly  connected  with  metal  from  the  top  of 
the  roof  to  the  bottom  of  it,  and  afterwards  to  the  well. 
exp.  xvn.  But  when  the  experiment,  with  the  long- 
pointed  conduflor  upon  the  model,  was  repeated,  and 
after  the  wheel  had  been  turned  an  equal  number  of 
times,  the  point  was  ftruck  as  it  palled  the  cylinder;  and, 
at  the  fame  inftant  alfo,  a very  fmall  ftream-like  explo- 
fion  appeared  between  the  two  cramps  at  the  corner  of 
the  model,  darting  as  it  feemed  from  one  to  the  other, 
in  a direction  that  was  rather  particular.  This  ftream- 
like  appearance,  I apprehended,  was  nothing  more  than 
the  effect  of  a fmall  explofion  in  confequence  of  the  mo- 
tion of  the  model. 
Mr.  wyatt,  who  is  well  acquainted  with  this  part  of 
Philofophy,  and  to  whom  great  obligations  are  due  from 
me  for  his  very  friendly  afliftance  in  the  whole  of  this 
undertaking,  having  obferved  this  appearance  feveral 
Vol.  LXVIII.  M m times, 
