PURIFICATION  OF  AMORPHOUS  PHOSPHORUS. 
439 
be  thoroughly  mixed,  and  pressed  rather  compactly  into  the  ves- 
sel in  which  they  are  to  be  kept ;  and  for  this  purpose  an  olive 
oil  jar,  well  cleaned,  answers  remarkably  well." — Pharmaceuti- 
cal Journal,  July,  1856. 
ON  THE  PURIFICATION  OF  AMORPHOUS  PHOSPHORUS. 
By  E.  Nickles. 
Amorphous  phosphorus,  incapable  of  spontaneous  inflamma- 
tion, is  obtained  by  keeping  ordinary  phosphorus  for  some  time 
at  a  temperature  of  between  446°  and  482°  F,  in  an  inert  at- 
mosphere ;  but  however  long  the  treatment  may  be  continued, 
there  is  always  a  portion  of  the  phosphorus  which  escapes  the 
transformation,  and  which  must  afterwards  be  got  rid  of  com- 
pletely in  order  to  avoid  destroying  the  essential  properties  of 
amorphous  phosphorus. 
The  disadvantages  of  the  mode  of  purification  proposed  by 
Schrcetter  have  long  been  recognized ;  it  is  founded  on  the  sol- 
vent action  of  sulphuret  of  carbon  upon  ordinary  phosphorus, 
whilst  it  has  no  action  upon  the  red  variety.  The  operation, 
therefore,  seems  very  simple,  but  in  practice  it  is  attended  with 
much  inconvenience  and  danger  ;  the  washings  are  interminable, 
and  the  chances  of  inflammation  increase  rapidly  with  the  quan- 
tity of  phosphorus  under  treatment.  To  avoid  this  danger, 
Schrcetter  recommends  that  the  filter  on  which  the  washing  is 
carried  on  should  be  kept  constantly  full  of  sulphuret  of  carbon, 
to  prevent  the  ordinary  phosphorus,  which  is  deposited  in  a 
very  finely  divided  state  upon  the  edges  of  the  filter,  from  caus- 
ing the  inflammation  of  the  whole ;  but  even  this  precaution  is 
not  sufficient  to  avoid  accidents. 
The  author  tried  several  methods  of  effecting  the  separation 
of  the  ordinary  phosphorus  by  chemical  means,  but  without  suc- 
cess, and  he  has  accordingly  availed  himself  of  the  different  den- 
sities of  the  two  bodies  to  effect  his  purpose,  by  agitating  them 
with  a  fluid  of  specific  gravity  intermediate  between  them.  Amor- 
phous phosphorus  has  a  specific  gravity  of  2-106,  and  ordi- 
nary phosphorus  of  1*77 ;  a  solution  of  chloride  of  calcium  of 
38°  to  40°  B.  will  serve  for  their  separation ;  the  ordinary  phos- 
phorus being  lightest,  floats  on  the  surface,  when  it  may  be 
