190  ME.  G.  GOEE  ON  THE  PEOPEETIES  OF  ELECTEO-DEPOSITED  ANTIMONY. 
deposited  to  i^-th  of  an  inch  thick  upon  a permanent  har-magnet  immersed  Teitically 
in  the  solution  of  tartar-emetic  and  dilute  hydrochloric  acid;  the  deposit  was  well 
washed,  and  after  remaining  in  this  state  two  days,  I struck  it  gently  with  a small  piece 
of  iron ; it  at  once  shattered  all  to  pieces  \vith  great  eTolution  of  heat  and  with  a small 
cloud  of  vapour,  emitting  an  odour  of  burnt  tartrates  and  hydrochloric  acid. 
21.  On  another  occasion  a deposit  |-th  of  an  inch  thick  formed  upon  one  side  of  a 
copper  medallion  in  the  same  liquid  had  been  removed  from  the  solution  and  lain  in 
water  thirty-six  hours,  I then  -wiped  it  dry  and  momentarily  apphed  the  flame  of  a candle 
to  a very  small  portion  of  its  edge ; the  whole  at  once  changed  -with  exceedingly  great 
evolution  of  heat. 
22.  Once  ha-ring  by  accident  feebly  struck  a deposited  bar  fths  of  an  inch  thick  against 
the  glass  containing  vessel  beneath  the  surface  of  the  liquid,  the  metal  was  immediately 
shattered  throughout ; many  pieces  fell  to  the  bottom  of  the  vessel,  and  a poweiful  sup- 
pressed bubbling  noise  as  of  heated  metal  plunged  into  water  occui’red. 
23.  At  another  time,  when  examining  the  thermo-electric  properties  of  a bar  4^  inches 
long  and  1^  inch  thick,  on  bringing  a heated  brass  mre  near  to  a very  small  portion 
of  one  end  of  the  bar,  a sudden  change  or  commotion  of  particles  took  place  throughout 
the  mass,  passing  rapidly  from  the  heated  part  to  the  opposite  end,  attended  by  the  pro- 
duction of  a few  very  minute  cracks,  and  with  great  evolution  of  heat,  rapidly  boiling  a 
few  drops  of  water  placed  upon  it. 
24.  And  on  another  occasion,  on  accidentally  touching  a cathode  covered  with  per- 
fect amorphous  deposit  against  the  anode,  the  change  with  considerable  hissing  noise 
occurred,  the  electric  spark  or  current  from  the  battery  being  in  this  case  the  apparent 
exciting  cause  of  the  phenomenon. 
25.  And  finally,  with  a rapidly  formed  and  perfect  specimen  of  dark  antimony 
deposited  upon  a swinging  helix  of  fine  copper  wire,  on  washing  it  first  in  dilute 
hydrochloric  acid  and  then  in  water,  and  gently  striking  it  Avith  a piece  of  glass,  it 
at  once  shattered  into  small  particles  with  considerable  force,  projecting  some  of  them 
to  a distance  of  10  feet,  apparently  by  converting  into  steam  the  adhering  particles  of 
water. 
26.  This  thermic  property  of  amorphous  antimony  is  retained  apparently  unimpaired 
upwards  of  2|  years;  a piece  deposited  in  October  1854  e-rolved  considerable  heat  by 
slight  percussion  in  May  1857.  The  change  appears  to  be  similar  to  the  molecular 
changes  of  sulphur,  selenium,  iodide  of  mercury,  &c.,  observed  by  Rittoef,  Eegxault, 
Webee,  and  others.  I have  never  found  that  the  phenomenon  could  be  repeated  uith 
the  same  specimen. 
27.  The  only  observed  exciting  causes  of  the  phenomenon  have  been  ordinary  heat, 
concentrated  solar  heat,  friction,  percussion,  fracture,  and  the  voltaic  spark.  Heat 
appears  always  to  determine  it,  whilst  with  thin  deposits,  slight  percussion  and  even 
fracture  have  frequently  failed.  Thick  pieces  Avill  bear  gentle  filing,  but  not  Aiolent 
fracture  at  ordinary  temperatures  without  the  change  occurring. 
