264  Papers  relative  to  an  Accident 
was  con  fider  ably  greater  than  the  quantity  difcharged 
into  the  rounded  end,  when  there  was  no  explofion. 
At  the  firft  rife  of  a difference  in  opinion,  refpeCting 
the  proper  termination  and  length  for  conductors,  I was 
prevailed  upon  by  fome  learned  members  of  the  Royal 
Society,  in  the  year  1764^0  publish  my  fentiments  upon 
that  fubjeCt.  Accordingly,  in  a letter  addreffed  to  the 
Marquis  of  Rockingham  (a>  (after  Rating  feveral  reafons 
againft  the  ufe  of  points,  as  I fuppofe  they  invited  the 
lightning)  I there  recommended  that  conductors  fhould 
not  only  be  rounded  at  their  ends,  but  be  made  conli- 
derably  fhorter  than  thofe  which  Dr.  franklin  con- 
tended for,  and  indeed  fhould  not  exceed  the  higheft 
part  of  the  building. 
In  the  following  experiment,  however,  I did  not  place 
the  pointed  conductor  below,  nor  upon  a level  with,  the 
higheft  part  of  the  building,  but  above  it,  even  one- 
third  of  the  length  of  that  in  the  twelfth  and  thirteenth 
experiment. 
exp.  xiv.  The  model  being  thus  furnifhed,  and  every 
thing  elfe  put  exactly  into  the  fame  circumftances  as  in 
the  thirteenth  experiment,  the  great  cylinder  was 
charged  by  twenty  turns  of  the  wheel.  Upon  letting  go 
the  model,  it  palled  the  cylinder  at  the  diftance  of  feven 
inches,  without  being  ft  ruck:  but  the  charge  that 
(a)  Phil.  Tranf.  vol.  LIV. 
remained 
