A  NEWLY-DISCOVERED  PROPERTY  OF  GUN-COTTON. 
Mr.  Wood  remarked,  with  reference  to  Dr.  Attfield's  inquiry,  that  the 
oolor  was  due  somewhat  to  the  method  of  making  the  liquor.  If  the 
liquor  were  made  with  an  appreciable  excess  of  ammonia,  and  put  into  a 
wide  bottle  of  some  size,  there  would  be  a  perceptible  tint  of  color.  But 
it  was  not  necessary  to  have  that  excess  of  ammonia  ;  it  was  possible  to 
re-neutralize  that  ammonia  by  acetic  acid  ;  and  if  they  did  that  there 
would  be  no  perceptible  color,  or,  at  any  rate,  so  far  as  his  experience 
went,  none  which  would  at  all  interfere  with  the  use  of  the  product  in 
pharmacy.  No  doubt  the  whole  thing-  was  a  matter  of  cost  and  of  hyper- 
criticism,  because  he  apprehended  that  if  there  were  a  slight  trace  of 
color  in  the  product,  as  a  medicine  it  would  not  in  the  slightest  degree 
interfere.  But  with  regard  to  the  cost  he  might  state  that,  even  in  using 
the  chemically  pure  bismuth  which  he  had  referred  to,  and  which  John- 
son and  Matthey  sold  at  40s.,  it  was  possible  to  make  a  liquor  at  3s.  a 
pound,  which,  he  believed,  was  the  price  the  original  solution  was  sold  at, 
although  that  was  only  one-third  the  strength  of  the  solution  made  accor- 
ding to  the  Pharmacopoeia ;  so  that,  if  chemically  pure  bismuth  was  re- 
quired, its  cost  ought  not  to  stand  in  the  way. — Lond.  Pharm.  Joum. 
Jan.,  1869. 
A  NEWLY-DISCOVERED  PROPERTY  OP  GUN-COTTON. 
It  has  been  found  that  the  explosive  force  of  gun-cotton 
may,  like  that  of  nitro-glycerin,  be  developed  by  the  exposure 
of  the  substance  to  the  sudden  concussion  produced  by  a  deto- 
nation ;  and  that  if  exploded  by  that  agency,  the  suddenness 
and  consequent  violence  of  its  action  greatly  exceed  that  of  its 
explosion  by  means  of  a  highly  heated  body  or  flame.  This  is 
a  most  important  discovery,  and  one  which  invests  gun-cotton 
with  totally  new  and  valuable  characteristics  ;  for  it  follows, 
as  recent  experiments  have  fully  demonstrated,  that  gun-cotton, 
even  when  freely  exposed  to  air,  may  be  made  to  explode  with 
destructive  violence,  apparently  not  inferior  to  that  of  nitro- 
glycerin, simply  by  employing  for  its  explosion  a  fuse  to  which 
is  attached  a  small  detonating  charge.  Some  remarkable  re- 
sults have  been  already  obtained  with  this  new  mode  of  explod- 
ing gun-cotton.  Large  blocks  of  granite  and  other  very  hard 
rock,  and  iron  plates  of  some  thickness,  have  been  shattered  by 
exploding  small  charges  of  gun-cotton,  which  simply  rested  upon 
their  upper  surfaces — an  effect  which  will  be  sufficiently  surpris- 
ing to  those  who  have  hitherto  believed,  as  every  one  has  be- 
