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ON  SOME  POINTS  OF  CHEMICAL  THEORY,  ETC. 
is,  all  the  hydrogen,  nitryl  bases.  Of  the  ammonia  there  is  left,  in 
the  first  case,  amide ;  in  the  second  case,  imide  ;  in  the  third, 
nitrogen  alone.  Hence  the  names  of  these  three  classes  of  bases. 
The  compounds  which  come  in  by  substitution,  are,  principally, 
the  five  positive  radicals,  methyl,  ethyl,  propyl,  butyl  and  amyl, 
already  mentioned.  The  names  of  all  the  bases,  thus  formed, 
end  with  the  syllables,  "  amine,"  as  an  abbreviation  of  the  word, 
ammonia.  Suppose  one  equivalent  of  methyl  to  be  substituted 
for  one  equivalent  of  the  hydrogen  of  ammonia  ;  the  amide  base, 
thus  formed,  is  called  methylamine.  In  a  similar  way  the  names, 
ethylamine,  propylamine,  butylamine,  amylamine,  &c,  are 
formed.  The  imide  bases  are  more  complicated  ;  for  here  two 
equivalents  of  hydrogen  undergo  replacement,  which  may  be 
done  by  two  equivalents  of  the  same  radical,  or  by  one  equiva- 
lent of  two  different  radicals.  Finally,  the  nitryl  bases  are 
formed  from  ammonia  by  the  replacement  of  all  three  of  the 
equivalents  of  hydrogen  ;  and  here  the  replacing  radicals  may 
be  all  alike  or  all  different,  or  two  alike  and  the  third  different. 
From  this  sketch  it  must  be  evident,  that  these  substitution- 
bases,  derived  from  ammonia,  are  very  numerous,  and,  at  the 
same  time,  difficult  to  name. 
Ammonium  is  considered  by  many  chemists  to  be  a  compound 
metal.  It  was  so  considered  by  Berzelius  ;  and  hence  he  gave  a 
metal  termination  to  its  name.  Now,  ammonium  is  the  type  of 
a  set  of  bases,  called  ammonium-bases,  which  are  even  more  in- 
teresting than  the  ammonia-bases.  Thus,  some  of  the  nitryl 
bases  are  capable  of  uniting  with  one  equivalent  of  a  radical, 
additional  to  the  three  equivalents  of  radicals,  already  present 
by  substitution.  These  four  equivalents  of  radicals  are,  of 
course,  united  with  one  equivalent  of  nitrogen;  and,  hence,  the 
compound  is  supposed  to  assimilate  in  constitution  to  ammonium, 
which  is  composed  of  four  equivalents  of  hydrogen  and  one 
equivalent  of  nitrogen.  For  example,  suppose  triethylamine, 
which  is  a  nitryl  base  containing  three  equivalents  of  ethyl,  to 
unite  with  one  additional  equivalent  of  ethyl—not  by  substitu- 
tion, for  there  is  nothing  for  it  to  replace,  but  by  what  may  be 
called  annexation— and  wTe  get  the  ammonium-base,  consisting 
of  one  equivalent  of  nitrogen  and  four  equivalents  of  ethyl, 
called  tetrethylammonium.    Now,  when  it  is  considered  that 
