University,  Dr.  Channing,  Mr.  Clarke,  and  Mr.  Jones.  In  Pro-
vidence, Rhode  Island,  these  gentlemen  have  been  carrying  on
together  experiments  seeking  to  perfect  the  form  of  apparatus
required,  and  I  am  happy  to  record  the  fact  that  they  communicated
to  me  each  new  discovery  as  it  was  made,  and  every  new  step
in  their  investigations.  It  was,  of  course,  inevitable  that  these


FIG.  22. — Hand  Telephone  (June  1877).
gentlemen  should  retrace  much  of  the  ground  that  had  been  gone
over  by  me,  and  so  it  has  happened  that  many  of  their  discoveries
had  been  anticipated  by  my  own  researches  ;  still,  the  very  honour-
able way  in  which  they  from  time  to  time  placed  before  me  the
results  of  their  discoveries  entitles  them  to  my  warmest  thanks,  and
to  my  highest  esteem.  It  was  always  my  belief  that  a  certain  ratio


PRODUCTION  OF  A  COMMERCIAL  INSTRUMENT        65

would  be  found  between  the  several  parts  of  a  telephone,  and  that
the  size  of  the  instrument  was  immaterial ;  but  Professor  Peirce
was  the  first  to  demonstrate  the  extreme  smallness  of  the  magnets
which  might  be  employed.  And  here,  in  order  to  show  the  parallel
lines  in  which  we  were  working,  I  may  mention  the  fact  that  two
or  three  days  after  I  had  constructed  a  telephone  of  the  portable
form,  containing  the  magnet  inside  the  handle,  Dr.  Channing
was  kind  enough  to  send  me  a  pair  of  telephones  of  a  similar
pattern,  which  had  been  invented  by  the  Providence  experimenters.
The  convenient  form  of  mouth-piece  shown  in  fig.  [22].  now
adopted  by  me,  was  invented  solely  by  my  friend  Professor
Peirce.1


FIG.  23. — Hand  Telephone  (December  1877).
