OF  THE  EADICAL,  MEECUEIC  METHYL. 
165 
This  impurity  is  not  easily  detected  until  the  liquid  is  burnt  with  oxide  of  copper,  when 
a httle  suhiodide  of  copper  generally  appears.  To  this  cause  is  referred  the  circumstance 
that  the  following  analyses  are  slightly  below  the  theoretical  value ; — 
I.  0'9774  grm.  burnt  with  oxide  of  copper,  gave  0'2335  grm.  water  and  0’3508 
grm.  carbonic  acid.  • 
II.  0'8082  grm.  burnt  with  oxide  of  copper,  gave  0T895  grm.  water  and  0’2870 
grm.  carbonic  acid. 
III.  0’7800  grm.  burnt  with  soda-lime,  gave  0'6718  grm.  mercury. 
IV.  1-2405  grm.  burnt  with  oxide  of  copper,  gave  1-0680  grm.  mercury. 
These  numbers  correspond  to  the  per-centages- 
I. 
II. 
III. 
IV, 
Carbon  9-78 
9-68 
Hydrogen  2-65 
Mercury  
2-60 
86-11 
86-09 
and  accord  with  the  formula 
C.H3Hg. 
Theory. 

Mean  of  Experiment. 
2 equivs.  of  Carbon  . 
. 'l2 
10-43 
9-73 
3 equivs.  of  Hydrogen 
3 
2-60 
2-63 
1 equiv.  of  Mercury  . 
. 100 
86-97 
86-10 
115 
100-00 
If  the  materials  be  dry,  the  decomposition 
of  iodide  of  hydrargyromethylium  by 
cyanide  of  potassium  is  very  simple,  and  may  thus  be  expressed  by  equation, — 
C,H3Hg„I+KCy=C,H3Hg+KI+Cy+Hg. 
I do  not  find,  however,  any  advantage  in  using  the  materials  absolutely  dry.  A little 
moisture  disintegrates  the  cyanogen,  and  the  resulting  gaseous  products  assist  in  removing 
the  vapour  of  the  new  body  from  the  seat  of  decomposition. 
From  the  constitution  of  this  compound  the  name  mercuric  methyl  is  proposed. 
Should  this  appellation  be  accepted  by  chemists.  Dr.  Feanklajstd’s  radical  would  be 
styled  mercurous  methyl. 
As  a corroboration  to  the  foregoing  analysis,  an  experiment  was  made  to  ascertain  the 
specific  gravity  of  the  vapour,  after  the  method  of  Dumas. 
Grammes.  Pressure.  Temperature. 
Weight  of  globe  filled  with  vapour  . 10-3245  769  mm.  117°  C. 
Weight  of  globe  filled  with  air  . . 9-9705  770  mm.  14°  C. 
Difference  = P = 0-3540 
Capacity  of  the  globe  =V— 57-0  cubic  centimetres. 
Volume  of  mercury  entering  the  globe=56-5  cubic  centimetres. 
Difference  = 0-5 
