s a stringed instrument which differs from the rest of its
class by being sounded neither with fingers like the lute nor with a bow
like the viol, but by means of a rotating wooden wheel. The melody
string (or strings) is not stopped directly by the finger as in the
violin, but by a series of keys manipulated by the performer, who need
not necessarily possess a musical ear since the stopping is arranged for
him. The Swedish nyckel-harpa--which I remember to have heard in
Stockholm--is the only other instrument in which the strings are stopped
by mechanical means. This instrument differs from the organistrum in the
fact that it is sounded by the ordinary fiddle-bow, and not by means of a
wheel. The organistrum is remarkable for having been "in constant and
popular use" from the tenth century up to the present day.

Clavichord and Virginal.

The clavichord, the earliest progenitor of the piano, originated in an
instrument in which the _tangent_ which struck a given string also acted
as a bridge to mark off the length of the vibrating portion and therefore
to determine the note produced. It is remarkable that (p. 115) this type
of instrument remained in use until the time of Sebastian Bach, when the
principle of "one tangent one string" replaced the more ancient system.

Of the clavichord Mr Dolmetsch (p. 433) writes that its tone is
comparable, as regards colour and power, "rather to the humming of bees
than to the most delicate among instruments. But it possesses a soul . . .
for under the fingers of some gifted player it reflects every shade of"
his "feelings like a faithful mirror. Its tone is alive, its notes can
be swelled or made to quiver just like a voice swayed by emotion. It can
even command those slight variations in pitch which in all sensitive
instruments are so helpful to expression."

[Picture: PLATE V. I. Viola d'Amore. 2. Cither Viol. 3. Hurdy-gurdy or
Organistrum]

The best known among the group of instruments to which the clavichord
belongs are the spinet and the harpsichord. I think that Browning's
musician who "played toccatas stately at the clavichord" must have
performed on one of the last-named instruments. In the spinet and the
harpsichord the strings are plucked, and therefore sounded, by small
points made of leather or of quill which are under the control of the
keyboard.

Mr Galpin (who is always interesting on evolution) points out that the