132 
Varieties. 
(  Am.  Jour.  Pharm.. 
t     Mar.  1, 1873. 
hydrogen  gas,  then  over  a  Bunsen  burner  for  10  minutes  and  for  15  to  20  min- 
utes over  a  blast  lamp.  The  product  sometimes  yields  a  yellow  phosphores- 
cent light,  and  when  this  is  the  case,  it  is  necessary  to  give  it  another  turn  over 
the  blast  lamp. 
Yellow. — Sulphate  of  baryta  6  parts,  charcoal  1  part,  fused  over  a  blast 
lamp,  at  first  afforded  no  light,  but  after  24  hours  gave  an  orange-yellow  light. 
It  may  not  be  generally  known  that  magnesium  liyht  will  suffice  to  bring  out 
all  the  effects  of  phosphorescence  nearly  as  well  as  sunlight. — Sci.  Amer.,  Feb^ 
22,  1873. 
Analysis  of  Commercial  Red  Ilxosphorus. — The  red  phosphorus  of  commerce, 
as  a  rule,  is  not  perfectly  pure.  It  frequently  contains  more  or  less  ordinary 
phosphorus,  and  as  this  gradually  oxidizes  in  the  air,  varying  quantities  of  phos- 
phorus and  phosphoric  acids  are  formed,  which  give  the  commercial  article  an 
acid  reaction  and  moist  appearance. 
The  determination  of  these  oxidation  products  offers  uo  special  difficulty, 
but  the  separation  and  determination  of  the  ordinary  phosphorus  is  much  less 
easy,  and  a  series  of  experiments  were  necessary  in  order  to  discover  a  good 
method  for  determining  all  the  constituents  of  commercial  red  phosphorus, 
Drs.  Fresenius  and  Luck  have  instituted  such  a  series  of  experiments  and  pub- 
lished the  method  of  analysis  chosen  by  them. 
The  red  and  ordinary  (yellow)  phosphorus  were  both  oxidized  and  deter- 
mined as  pyrophosphate  of  magnesia.  The  red  and  yellow  phosphorus  were 
next  separated  by  the  bisulphide  of  carbon,  and  the  weight  of  the  former  found, 
Subtracting  the  weight  of  the  red  phosphorus  from  the  total  amount  of  phos- 
phorus found  above,  gives  the  amount  of  yellow  phosphorus.  As  a  check  on 
this,  the  yellow  phosphorus  in  the  bisulphide  solution  is  oxidized  with  iodine 
aud  then  converted  into  pyrophosphate  of  magnesia. 
The  following  is  the  average  of  two  analyses  : 
Per  cent. 
Total  phosphorus,         .....  93*30 
Yellow  phosphorus,  .....  0*56 
Red  phosphorus,  .  .  .  .  .  92  63 
Phosphorous  acid.    ......  1*308 
Phosphoric  acid,  .  .  .  .  0*880 
Water  aud  impurities,        .....  4*622 
— Journ.  Applied  Chem.,  Jan.,  1873. 
Action  of  Ethei- upon  Iodides — Dr.  J.  B.  de  Vry  — The  author  states,  in  ref- 
erence to  an  observation  made  by  Ferrieres  concerning  the  decomposition  of 
iodides  by  ether,  that  several  years  ago  he  tried  a  similar  experiment  leading 
to  the  same  result  ;  but  when  the  ether  of  commerce  was  first  thoroughly 
shaken  up  with  a  concentrated  solution  of  sulphate  of  protoxide  of  iron,  and 
next  with  milk  of  lime,  and  then  rectified  by  distillation,  no  action  of  the  ether 
upon  the  iodides  was  observed.  The  author  further  observed  that,  while  he  re- 
sided in  Java,  he  always  ordered  the  ether  sent  to  him  from  Europe  to  be  rec- 
