3 oa  Papers  relative  to  an  Accident 
depends  more  upon  the  length  of  the  metallic  body,  than 
upon  the  quantity  of  its  matter  or  furface. 
It  was  upon' the  idea  of  the  velocity  of  the  fluid  being 
thus  increafed,  that  I apprehended  gun-powder  might  be 
fired  without  the  leaffi  appearance  of  a fpark . The  fue- 
cefs  of  this  experiment  was  an  inducement  to  try  kun- 
K-ELL's  phofphorus,  which  was  made  by  Dr.  higgins. 
The  moment  this  inflammable  fubftance  was  brought 
very  near  the  furface  of  the  brafs  drums,  it  burft  into  a 
blaze;  and  common  tinder,  applied  in  the  fame  manner, 
was  fet  on  fire  the  inftant  when  it  was  brought  fo  near  as 
to  touch  the  metal : but  there  was  not  the  leaf!  appear- 
ance of  a fpark  in  any  of  thefe  experiments. 
The  method  taken  to  fire  the  gun-powder  was  this : 
upon  a ftaff  of  baked  wood  a Item  of  brafs  was  fixed, 
which  terminated  in  an  iron  point  at  the  top.  This  point 
wa&put  into  the  end  of  a fmall  tube  of  Indian  paper,  made 
fomewhat  in  the  farm  of  a cartridge,  about  one  inch  and 
a quarter  long,  and  about  two-tenths  of  an  inch  in  diame- 
ter. When  this  cartridge  was  filled  with  common  gun- 
powder (unbruifed)  the  wire  of  communication  with  the 
well  was  then  fattened  to  the  bottom  of  the  brafs  ftem. 
Being  fo  circumftanced,  and  whilft  the  charge  in  the 
great  cylinder  and  wire  was  continually  kept  up  by  the 
motion  of  the  wheel,  the  top  of  the  cartridge  was  brought 
fo 
