From the book, "Piano", by David Crombie; there are two photographs
with this caption:
"Dulcitone by Thomas Machell & Sons, Glasgow, c.1920."
"The 'Dulcitone' was invented by Thomas Machell in 1860, although not
perfected until 1880. It is usually described as a 'tuning-fork'
instrument. This five-octave example uses a down-striking version of
the English grand action. The inverted action assembly can be seen
on top of the casework in the picture below. The jack (or hopper) is
beneath the front of the key. Each hammer strikes a U-shaped metal
bar mounted in rubber. The sound bears little relationship to that
of a piano but the instrument feels similar to play.
The lack of a real frame makes the Dulcitone relatively light and
portable. It was the most popular of the early 'tuning-fork'
instruments. Other examples included the 'Typophone', the 'Adiaphon'
and the 'Euphonium'. The most famous, however, was the electric
piano designed by Harold Rhodes in the late 1950s."