Coming back to earth, I’ll try and tell you what happened that day. In
the experiments on the harmonic telegraph, Bell had found that the
reason why the messages got mixed up was inaccuracy in the adjustment of
the pitches of the receiver springs to those of the transmitter. Bell
always had to do this tuning himself, as my sense of pitch and knowledge
of music were quite lacking—a faculty (or lackulty) which you will hear
later became quite useful. Mr. Bell was in the habit of observing the
pitch of a spring by pressing it against his ear while the corresponding
transmitter in a distant room was sending its intermittent current
through the magnet of that receiver. He would then manipulate the tuning
screw until that spring was tuned to accord with the pitch of the whine
coming from the transmitter. All this experimenting was carried on in
the upper story of the Williams building, where we had a wire connecting
two rooms perhaps sixty feet apart looking out on Court Street.
[Illustration: _Prof. Bell’s Vibrating Reed—Used for a Receiver_]