nTelharmoniumAn instrument for producing music (Tel*har"mo*ny), at a distant point or points by means of alternating currents of electricity controlled by an operator who plays on a keyboard. The music is produced by a receiving instrument similar or analogous to the telephone, but not held to the ear. The pitch corresponds with frequency of alternation of current.
Webster's Revised Unabridged Dictionary
Gr. th^le far + harmolium,
Just why the telharmonium has not made good its promises of popularity I do not know.
"Mark Twain, A Biography, 1835-1910, Complete" by Albert Bigelow Paine