1 
ANov°tm2RM'}         Fusion  of  Metallic  Arsenic.  497 
senic  cannot  be  fused,  but  passes  directly  from  the  solid  into  the  va- 
porous state,  and  that  an  attempt  to  secure  increased  pressure  by 
using  a  sealed  tube  only  results  in  bursting  the  tube.  The  statement 
by  Landolt*  (given  apparently  without  further  details),  that,  by  using 
a  glass  tube  enclosed  in  one  of  iron,  the  metal  heated  for  some  time 
j  to  low  redness  under  pressure  may  be  melted  into  globules,  was  no- 
ticed only  after  the  experiments  to  be  mentioned  had  been  made. 
Arsenic,  in  the  form  of  small  fragments  and  coarse  powder,  was 
placed  in  a  thick  barometer-tube  of  soft  glass  and  of  small  bore,  well 
sealed  at  both  ends  and  enclosed  in  a  piece  of  wrought  iron  gas-tubing 
closed  at  each  end  by  an  iron  screw  cap  ;  the  space  between  the  two 
tubes  was  filled  with  sand  well  shaken  down,  and  the  whole  was  heated 
to  redness  by  a  charcoal  fire.  Another  similar  iron  tube  placed  be- 
side the  former  served  to  contain  several  little  glass  tubes  with  sam- 
ples of  different  metals  whose  fusion  might  afford  some  indication  of 
the  temperature  at  which  that  of  the  arsenic  occurred. 
Arsenic  thus  treated  was  found,  on  cooling,  to  have  fused  into  a 
perfectly  compact  crystalline  mass,  moulded  to  the  shape  of  the  tube 
of  steel-grey  color  and  brilliant  lustre,  of  sp.  gr.=5'709  at  19°  C. 
It  possessed  a  considerable  degree  of  cohesive  strength  as  compared 
with  common  sublimed  arsenic,  and  even  seemed  to  exhibit  faint  traces 
of  flattening  before  crushing  under  the  hammer.  It  gradually  tar- 
nished on  exposure  to  the  air,  and  presented  all  the  chemical  proper- 
ties of  ordinary  crystalline  arsenic  obtained  by  sublimation.  The  tem- 
perature required  for  fusion  lies  between  the  melting-points  of  anti- 
mony and  silver. 
The  glass  tube  used  was  found  greatly  distended  by  the  tension  of 
the  vapor,  and  the  siliceous  sand,  even  when  of  the  purest  kind  (from 
Pontainebleau),  and  previously  well  washed  with  hydrochloric  acid, 
and  then  with  water,  was  cemented  together  (in  a  way  very  interest- 
ing in  connection  with  the  history  of  metamorphism)  into  a  kind  of 
artificial  sandstone.  Specimens  of  fused  and  semi-fused  arsenic,  and 
of  the  tubes  surrounded  by  a  thick  crust  of  compacted  sand,  were  ex- 
hibited to  the  Section. 
— Chem.  News  [London],  August,  30,  1872. 
*  Verhandl.  d.  niederrhein.  Gesellscha/t,  August  4,  1S59,  quoted  iu  Will's 
Jahresbericht,  for  1859,  S.  182. 
32 
