scheme artificial harmonic (transposition within chord)

[Rob Canning]

hello,
i am trying to get scheme to automate artificial harmonics so i dont 
need to specify the pitch of the note written up the perfect fourth
i am running in to the problem of scheme not evaluating the variable 
once put inside the <chord>
(i get errors regarding /lilyvartmpc /)

where lies the error or is there a better way to do this - am slightly 
suprised there is not a build in function for this... maybe there is?

artHarm = #(define-music-function (parser location note)
                                    (ly:music?)
 #{
         < $note \transpose c f  $note \harmonic >
 #})

{ \artHarm b }

thanks
rob