114     New  Allotropic  Modification  of  Phosphorus.  {AV£TOi,u7A£*" 
posed  to  direct  contact  with  air  in  a  dark  room.  We  regard  this  very 
unusual  property  as  suggestive  of  an  allotropic  state. 
Apparently  two  modifications  of  solid  phosphorus  result  from  the 
solidification  of  the  liquid  variety.  One  is  tough  and  waxy,  like  or- 
dinary phosphorus  ;  the  other  brittle  and  crystalline  in  texture.  The 
best  liquid  specimens  in  solidifying,  always  gave  the  second  variety — 
indifferent  ones,  the  first.  We  therefore  regard  that  producing  the 
second,  as  the  true  liquid  modification. 
Rough  experiments  were  made  in  order  to  ascertain  whether  the 
liquid  modification  underwent  any  change  of  volume  by  solidification. 
For  this  purpose  a  specimen  was  placed  in  a  test  tube  filled  with  wa- 
ter, and  a  small  capillary  tube  also  filled,  passed  down  into  the  vessel, 
and  attached  to  it  by  a  well-fitted  cork.  Any  appreciable  change  in 
the  volume  of  the  phosphorus  would  cause  a  rise  of  the  water  in  the 
capillary  tube.  We  expected  to  find  a  slight  change,  but  none  was 
observable.  This  result  was  probably  owing  to  the  expansion  occa- 
sioned by  the  heat  emitted  on  solidification,  exactly  balancing  the 
contraction  caused  by  the  passage  from  the  liquid  to  the  solid  state. 
No  sudden  movement  of  the  capillary  column  was  noticed  on  the  in- 
stant of  solidification. 
In  order  to  see  whether  the  liquid  state  was  due  to  hydrogen  in  com- 
bination with  the  phosphorus,  we  placed  small  pieces  of  the  solid  va- 
riety in  a  tube,  whose  ends  were  afterwards  drawn  out  into  capillaries,, 
and  then,  passing  hydrogen  from  a  small  generator  through  the  tube, 
melting  the  phosphorus.  A  liquid  resulted,  possessing  different 
properties  from  that  formed  by  boiling  in  potassium  hydrate.  It 
was  quite  mobile,  of  an  amber  color,  and  on  solidifying,  produced  the 
waxy  material. 
A  fact,  not  perhaps  well  known,  was  noticed  during  the  conduct  of 
the  experiment.  A  colorless  gas  was  evolved  from  the  free  end  of 
the  tube  which  was  spontaneously  inflammable  in  air.  The  heat  of 
this  flame  was,  however,  so  slight  as  to  render  it  incapable  of  igniting 
the  hydrogen  issuing  with  it. 
To  test  the  effect  of  the  boiling  point  upon  the  production  of  the 
allotropic  modification,  specimens  were  prepared  by  long  boiling  in 
saturated  solution  of  chloride  of  zinc.  We  were  unsuccessful  in  ob- 
taining the  liquid  modification.  A  high  boiling  point  cannot,  there- 
fore, be  assigned  as  the  entire  cause  of  the  change. 
The  substance  in  question  may  be  merely  a  very  pure  phosphorus, 
