512 
ON  WHITE  GUNPOWDER. 
ON  WHITE  GUNPOWDER. 
By  F.  Hudson,  Esq. 
Having  lately  prepared  different  samples  of  white  gunpowder 
(according  to  the  receipt  of  Dr.  J,  J.  Pohl,  given  in  the  Qhemi- 
cal  News,  July  6)  for  some  military  engineering  experiments,  I 
have  tried  the  process  of  separately  grinding  the  materials,  viz. 
chlorate  of  potash,  ferrocyanide  of  potassium,  and  cane  sugar, 
and  then  mixing  them  ;  also  grinding  them  together  with  a  little 
water  added,  and  then  dried  at  a  temperature  of  about  150^, 
I  find  that  those  samples  which  were  prepared  moist  and  then 
dried  are  more  easily  exploded  than  those  prepared  by  the  dry 
process.     In  fact,  one  sample  exploded  in  an  open  porcelain 
dish  by  simple  friction  with  a  spatula  with  which  one  of  my 
assistants  was  crushing  some  of  the  larger  pieces.  Through 
the  explosion  he  was  laid  up  for  several  weeks  and  nearly  lost 
his  eyesight.    No  samples  prepared  dry  are  as  explosive  as  those 
prepared  moist,  the  addition  of  water  causing  a  more  perfect 
mixing  of  the  particles  of  its  chemical  constituents  than  can 
be  effected  by  the  dry  grinding  process.    This  accounts  for  the 
greater  danger  attending  the  use  of  white  gunpowder  prepared 
in  the  moist  way. 
A  cannon  loaded  with  white  gunpowder  goes  off  on  the  ap- 
plication of  a  few  drops  of  sulphuric  acid  (equally  as  well  as 
with  a  light  applied)  to  its  touch-hole. 
This  property  of  the  gunpowder  may  possibly  be  applied  to 
some  advantage  in  the  construction  and  preparation  of  bomb 
shells  for  long  ranges.  The  shells  would  not  explode  (if  filled 
with  the  white  powder  and  containing  a  glass  vessel  with  sul- 
phuric acid)  until  they  struck  the  object.  No  useless  explosion 
of  the  shell  could  take  place  in  the  air,  as  is  too  often  the  case 
with  the  ordinary  fusee  shell. 
Its  expansive  or  explosive  force  is  also  twice  that  of  common 
gunpowder.  In  all  experiments  performed  with  this  white  gun- 
powder, care  must  be  taken  not  to  compress  it  too  violently ; 
otherwise  accidents  may  frequently  occur.  A  blow  with  a 
hammer  upon  stone  with  some  of  the  powder  upon  it  explodes 
all  samples  that  I  have  prepared — Cliem,  News,  London^  Aug., 
1861. 
