Am,  Jour  Phann. ) 
April,  1879.  J 
Chemical  Notes', 
CHEMICAL  NOTES. 
By  Prof.  S.  P.  Sadtler. 
Inorganic  Chemistry.— The  beautiful  experiments  of  Messrs.  Cail- 
letet  and  Pictet  on  the  liquefaction  of  the  so-called  permanent  gases- 
(this  journal,  p.  185,  1878)  are  already  bearing  fruits  in  inciting  others 
to,  similar  work.  M.  Ogier  has  just  accomplished  the  liquefaction  of 
hydrogen  silicide  (H4Si).  This  was  done  with  the  Cailletet  apparatus. 
At  ordinary  temperatures  (about  io°C.)  hydrogen  silicide  is  not  lique- 
fied, even  under  a  pressure  of  200  to  300  atmospheres,  but  if  cooled  a 
much  smaller  pressure  suffices.  Thus,  at  — 110  it  is  liquefied  under  a. 
pressure  of  50  atmospheres  ;  at  — 50  under  a  pressure  of  70  atmos- 
pheres.; at  — 1°  under  a  pressure  of  100  atmospheres,  while  at  o°  it 
remains  gaseous,  even  under  150  to  200  atmospheres.  What  may  be 
called  the  critical  point,  therefore,  seems  to  be  just  under  zero.  In 
these  conditions  of  liquefaction  it  resembles  marsh  gas  (CH4)  with 
which  it  has  great  chemical  analogy. — Comptes  Rendus,  pp.  88,  236. 
O.  Emmerling  has  made  some  experiments  on  the  preparation  of 
metallic  phosphides,  working  with  great  pressure  obtained  by  the  use  of 
sealed  tubes.  He  considers  that  in  this  way  only  can  the  metal  be 
made  to  take  up  the  maximum  amount  of  phosphorus  and  yield  a 
compound  of  definite  chemical  composition.  The  metal  was  placed 
in  a  glass  tube,  having  been  previously  drawn  out  to  wire,  and  covered 
with  an  excess  of  phosphorus.  The  tube  was  then  completely 
exhausted  and  fused  shut  while  in  this  state,  the  phosphorus  having,  in 
the  mean  time,  melted.  The  tubes  were  always  opened  in  an  atmos- 
phere of  carbonic  acid  gas  so  as  to  avoid  oxidation  of  the  products  or 
of  the  excess  of  phosphorus.  The  results  with  different  metals  were 
as  follows  : 
Phosphorus  and  copper  yielded  a  brittle,  crumbling  mass  of  dull 
silvery  lustre,  containing  66*5  per  cent.  Cu.  This  would  appear  to  be 
CuP,  which  demands  66  4  per  cent.  Cu.    Sp.  gr.  5'i4. 
Phosphorus  and  magnesium  yielded  a  blueish-gray  infusible  mass, 
which  rapidly  oxidized  to  magnesium  phosphate  so  that  it  could  not  be 
analyzed. 
Phosphorus  and  aluminium  yielded  no  compound. 
Phosphorus  and  mercury  yielded  no  compound. 
Phosphorus  and  silver  yielded  a  black,  very  brittle  mass  of  the 
