from  Lightning  at  Purfleet.  2 7 1 
Before  thefe  experiments  are  related,  it  is  proper  to 
mention  a material  circumftance,  which  hath  hitherto 
been  unnoticed. 
At  the  time  the  accident  happened  at  Purfleet,  a great 
quantity  of  rain  fell,  by  which  the  wails  of  the  Board- 
houfe,  being  made  very  wet,  were  difpofed  to  admit 
more  readily  the  lightning  palling  upon  the  furface, 
though  yet  not  fo  readily  as  a covering  of  metal  would 
have  done.  This  particular  circumftance  of  the  rain  will 
be  attended  to  in  its  place. 
But  firft  it  may  be  proper  to  fliew  the  effects  of  a me- 
tallic communication.. 
To  this  end,  I covered  the  top  of  the  parapet  quite 
round  with  tin-foil ; and  becaufe  the  copeing  projected  a 
little  over  the  parapet,  under  which  no  rain  could  poffi- 
bly  get,  I left  a fmall  interval,  proportional  to  it,  unco- 
vered with  that'  metal.  This  interval  was  on  the  oppofite 
lide  of  the  model,  which  anfwered  to  the  South-fide  of 
the  building  where  the  other  fpouts  were  fixed.  Then 
from  that  interval  I palled  a broad  flip  of  tin-foil  down . 
to  the  bottom  of  the  model,  where  having  fixed  a fmall 
brafs  ftaple  to  hook  a wire  upon,  I fattened  the  other  end 
of  it  to  the  wire  which  communicated  with  the  well.  At 
the  fame  time  care  was  taken  to  fallen  another  wire  in  < 
the  fame  manner,  which  communicated  with  the  oppo- 
fite. 
