8ton^3,  tranaport,  and  use  of  these  explosives,  and  the  rapid  develop-
ment of  the  intlustry  nece^tated  the  introduction  of  the  Explosives  Act  of
1875.  In  1876  the  authorised  list  of  explosives  comprised  twelve  kimb
only,  but  in  1907  it  had  risen  to  182.  In  addition,  during  thia  period,
108  explosives  had  been  passed  by  the  Home  Office  after  examination  by
Duprt?,  and  over  one  hundred  had  been  rejected  by  his  advice.  He  thus
investigated,  during  a  period  of  thirty-aix  years,  nearly  four  hundred  entirely
new  explosives  of  the  moat  varied  comi>osition,  and  farther  examined,  nt
frequent  intervals,  all  explosives  ini ported  into  England,  as  to  safety.  In
tlie  course  of  this  work  he  liad  often  to  evolve  original  methods  of  aBalysis  or
of  testing  for  safety,  and  in  this  latter  direction,  especially,  he  rendered  great
services  to  the  Go%*crumtmt.  and,  indirectly,  to  the  public.
