432 
AMMONIA  GUNPOWDER. 
combined  with  tannic  acid,  as  is  the  case  in  all  coffees,  pure 
caffeine  yielding  different  products  of  decomposition,  among 
which  is  cyanogen.  In  roasting  coffee  part  of  the  caffein  is 
volatilized  together  with  some  methylammin,  while  the  larger 
amount  remains  with  the  coffee  itself.  Half  of  the  caffein  of 
the  coffee  is  decomposed  in  this  way  ;  one  sample,  which  before 
roasting  tested  1-45  p.  c,  yielding  afterwards  only  0*65  p.  c.  of 
caffein.  The  temperature  at  which  these  changes  are  effected 
is,  in  the  case  of  green  coffee  (Porto  Rico),  275°  C.  ;  in  the  case 
of  yellow  coffee  (Java),  250—255°  C. 
Caffein  is  soluble  in  bisulphide  of  carbon  and  in  benzole ;  in 
benzole  especially,  to  such  an  extent  that  it  may  be  used  with 
advantage  for  the  preparation  of  the  pure  alkaloid. — Drug.  Cir- 
cular ^  New  York,  Jiine^  1870. 
AMMONIA  GUNPOWDER. 
By  M.  a.  Jouglet. 
The  owners  of  the  Nora-Gyttorp  Powder  Mill,  Sweden,  have 
brought  out  a  new  kind  of  powder,  which  contains,  it  appears, 
a  mixture  of  nitrate  of  ammonia  and  nitrate  of  potassa  (with 
what  other  substance  is  not  said).  This  material  is,  according 
to  some  accounts,  a  more  powerful  explosive  than  nitro  glyce- 
rin,  and  cannot  be  ignited,  or  made  to  explode,  but  by  the  im- 
pact of  a  blow,  or  a  falling  weight,  or  by  the  detonation  of  a 
small  cartridge  containing  common  gunpowder.  Experiments 
made  at  a  military  establishment  at  Berlin  with  this  powder 
have  proved  that,  while  ordmary  gunpowder,  gun-cotton, 
nitroglycerin,  and  dynamite  take  fire  the  moment  flame  is 
approached,  this  powder  did  not  do  so.  As  regards  the  effect 
of  the  impact  of  a  blow  of  a  falling  weight  (the  same,  of  course, 
in  each  case),  ordinary  gunpowder  requires  for  explosion  that 
the  weight  falls  from  a  height  of  between  4  and  5  ft. ;  nitro- 
glycerine, 1 J  ft. ;  dynamite,  2}  ft. ;  and  ammonia  gunpowder, 
between  12  and  15  ft.  A  sample  having  been  sent  to  France 
from  Berlin  did  not,  the  author  says,  confirm  the  high  opinion 
this  substance  is  thought  worthy  of  in  Prussia. — Chemical 
News,  London,  Feb.  2bth,  1870. 
