166 
ME.  G.  B.  BBCKTON  ON  THE  ISOLATION 
w^=:weight  of  one  cubic  inch  of  air  at  14°  C.  = 0‘001230. 
w^,=weight  of  one  cubic  inch  of  ah’  at  117°  C.  = 0’000905. 
By  introducing  these  numerical  values  into  Mullee’s  formula,  we  have 
Specific  gravity  ■) P + Vm*  _0-42411* „ 
of  the  vapour/  O’bsilS 
The  weight  represented  by  the  formula  H3  Hg,  divided  by  the  experimental  density, 
115 
gives  the  quotient  g;7^  = 13’87.  Supposing  the  constituents  of  mercuric  methyl  con- 
densed into  two  volumes  of  vapour,  the  more  accurate  number  14’46  should  have  been 
obtained. 
115  _ 
The  theoretical  density  of  the  vapour  of  mercuric  methyl  is  14.46" 
Although  the  salts  of  mercurous  methyl  are  remarkably  stable,  the  sulphate  for 
instance  resisting  for  some  time  the  action  of  boiling  sulphuric  acid,  they  may  be  made 
to  part  with  a portion  of  their  mercury  by  a variety  of  means.  The  action  of  sodium 
on  mercuric  methyl  is  very  slow,  and  it  is  only  after  long  boiling  that  the  sodium  becomes 
amalgamated,  with  the  liberation  of  a gas  which  is  doubtless  methyl.  The  action  of 
sodium,  on  the  other  hand,  upon  iodide  of  mercurous  methyl,  is  suificiently  great  to 
cause  explosion  when  gently  heated.  If  the  sodium  be  previously  amalgamated,  and 
reduced  to  small  pieces,  the  volatile  products  Avill  be  found  to  contain  a considerable 
quantity  of  mercuric  methyl.  The  same  decomposition  is  also  efiected  through  lime  or 
hydrate  of  potassa.  A higher  temperature  appears  to  be  requhed  to  induce  the  change, 
and  accordingly  the  amount  of  mercuric  methyl  obtained  is  comparatively  small. 
Marsh-gas  is  liberated  in  the  decomposition  according  to  the  equation 
2(C,  H3  Hg3  l)+2KO  H0=C3  H3  Hg+2KI+C,  H,-f  3HgO+HO. 
Decompositions  of  Mercuric  Methyl. 
Mercuric  methyl  exhibits  no  tendency  to  unite  with  the  electro-negative  elements, 
such  as  oxygen  and  chlorine.  All  attempts  to  produce  such  compoimds  lead  to  the 
destruction  of  the  substance. 
Mercuric  methyl  sinks  in  concentrated  sulphuric  acid,  and  liberates  bubbles  of  a gas 
which  burns  with  a pale  non-luminous  flame.  This  evolution  is  assisted  by  a gentle 
heat. 
One  volume  of  this  gas,  when  exploded  in  the  eudiometer  with  a mixture  of  oxygen 
and  air,  gave,  after  due  correction  for  pressure  and  temperature,  a contraction  equal  to 
two  volumes,  and  subsequently  by  potash,  an  absorption  equal  to  one  volume  of  carbonic 
acid. 
This  deportment  shows  the  gas  to  be  hydride  of  methyl  or  marsh-gas. 
After  the  decomposition  of  mercuric  methyl  by  an  acid,  the  solution  contains  an 
abundance  of  that  salt  of  mercurous  methyl  which  corresponds  to  the  acid  employed. 
