480 
ON  EMULSIONS. 
was  tamped,  leaving  a  depth  of  seven  feet.  Nearly  three  pints 
of  the  nitro-glycerin  was  then  poured  in — it  occupied  five  feet; 
a  match  and  stopper  were  then  applied,  as  stated,  and  the  mine 
sprung.  The  effect  was  so  enormous  as  to  produce  a  fissure  fifty 
feet  in  length,  and  another  of  twenty  feet.  The  total  effect  has 
not  yet  been  ascertained,  because  it  will  require  several  small 
blasts  to  break  the  blocks  that  have  been  partially  detached  by 
this. — London  Chem.  JVews,  August  25,  1865. 
ON  EMULSIONS. 
By  Mr.  Barnard  S.  Proctor. 
In  our  published  list  of  subjects  for  investigation,  my  name 
stands  as  having  undertaken  the  study  of  emulsions.  At  the 
time  this  promise  was  made,  I  was  aware  that  I  could  not  work 
it  to  a  satisfactory  conclusion  in  the  course  of  the  year,  but  cir- 
cumstances soon  occurred  which  made  it  impossible  even  to  get 
it  so  far  advanced  as  to  justify  a  report  of  progress  ;  unwilling, 
however,  to  let  the  meeting  of  the  Conference  for  1865  pass 
without  some  communication  from  myself,  I  may  state  to  you 
how  the  subject  arose,  and  what  I  had  proposed  to  do. 
The  subject  suggested  itself  to  me,  some  years  ago,  from  ob- 
serving that  a  mixture  which  was  made  with  balsam  of  copaiba 
and  an  alkali,  was,  from  some  cause,  a  very  imperfect  emulsion, 
and  that  a  further  addition  of  alkali  rendered  it  still  less  satis- 
factory. At  another  time  I  noticed  that  in  making  Locock's  lo- 
tion (from  Beasley's  formula),  a  less  perfect  emulsion  was  formed, 
when  strong  solution  of  ammonia  was  used,  than  when  it  was 
prepared  with  that  of  *960  sp.  gr.  ;  and  that  it  was  most  perfect 
when  the  mixture  was  so  long  rubbed  in  the  mortar,  that  great 
part  of  the  ammonia  evaporated.  These  were  crude  and  casual 
observations.  I  was  not  prepared  to  say  whether  it  was  much 
rubbing  or  much  evaporation  which  was  the  cause  of  the  superi- 
ority in  the  latt:r  case,  but  I  was  impressed  with  the  subject  as 
being  one  worth  looking  into.  I  remembered  often  observing 
that  soap  was  much  more  effectual  than  caustic  alkali,  for  re- 
moving grease  from  bottles ;  I  bore  in  mind  also,  that  most,  if 
not  all  the  natural  emulsions,  were  not  far  removed  from  neutral- 
