Grove's dictionary of music and musicians

a:
in the Gregorian system of notation the lozenge
remains in use to the present day.
Until the heginning of the 17th century,
the Semibreve represented one -third of a
Perfect Breve, and the half of an Imperfect
one. In the Greater Prolation it was equal
to three Minims ; in the Lesser to two. In
Prolation—or, as we should now call it, triple
for, apart from the traditions of the Sistine
Chapel, early writers have left a very definite
rule for our guidance. The Thesis and Arsis
of the Lesser Prolation, they say, represent the
beats of the human pulse. Now, the rapidity
of the human pulse, taking into calculation the
variations exhibited at all ages, and in both
sexes, ranges between 66"7 and 140 per minute ;
allowing, therefore, for roughness of calculation,
we may say that the compositions of Josquin
des Prfe, and Palestrina, may be safely interpreted
between
J =60, and J =140—
SEMICHORUS SEMIQUAVER 411
either case it was accepted as the norm of all
other notes, and was held to constitute a
complete measure or stroke. In the Greater
time—this stroke was indicated by a single
down-beat of the hand, representing what we
write as a dotted Semibreve. In the Lesser
Prolation—the common time of the modern
system—it was indicated by a down and an
up beat, called respectively the Thesis and the
Arsis of the measure. It will be understood
that these two beats represented two minims ;
and, happily for us, we are not left altogether
in doubt as to the average pace at which these
two Minims were sung, in the great polyphonic
compositions of the 15th and 16th centuries
sufficiently extended range for any conductor.
In modern music the Semibreve retains
more than one of the characteristics that distinguished
it in the 16th and 16th centuries.
It is now, indeed, the longest instead of the
shortest note in common use, for the employment
of the Breve is altogether exceptional
but it is none the less the norm from which
all other notes are derived. We may say that,
of all the notes now in use, the Semibreve is
the one which unites us most closely to the
system of those who invented the germ of the
method we ourselves follow ; and it furnishes
the safest guide we know of to the right understanding
of their works. w. s. K.
SEMICHORUS, i.e. Half- chorus ; a word
used to denote a kind of antiphonal effect produced
by employing half the number of voices
at certain points, and contrasting this smaller
body of sound with the fuU chorus. M.
SEMICEOMA (Lat. Semiehroma ; Eng.
Quaver, or Semiquaver). The Italian name
for the Semiquaver. Old writers, however,
sometimes apply the term Croma to the crotchet,
and Semicroma to the quaver ; and, so vague
was once the distinction between the two, that
even Baretti, writing as late as 1824, makes
the word 'Croma' signify 'a crotchet or
quaver." The etymology of the word Chroma
is derived from the very early custom of using
red notes intermixed with black ones. The
red notes being sung more quickly than the
black ones, the duration of a red minim was a
little longer than that of a black Semiminim
(or crotchet) ; and the note was called Chroma
on account of its colour. [See Notation,
Quaver.] w. s. e.
SEMIFUSA. The Latin name for the Semiquaver
; but sometimes applied to the Quaver
also. The etymology of the term is not very
clear. The most probable theory is that which
traces it to a fancied resemblance between the
early form of the Quaver, sind that of a spindle
(fustis). [See Notation, Quaver.] w. s. r.
SEMIMINIMA major and minor (Eng.
Greater, and Lesser iralf-Minim = Crotchet,
and Quaver ;
Ital. Croma e Semicroma ; Germ.
Viertel und Achtel ; French Noire et Croche).
Though the Minim was so called, because, at
the time of its invention, it was the smallest
(i.e. the shortest) of all notes, composers soon
found it convenient to divide it in half, and
even into four parts. Franchinus Gafurius,
quoting from Prosdocimus de Beldemandis,
describes and figures these divisions in his
Practica Mwsiaae, printed in 1496. The Greater
Semiminima, the equivalent of the modern
crotchet, was a black lozenge -headed note,
with a tail, ;
^ the Lesser Semiminima, now
called the quaver, was a similar note, with a
single hook, ^. Sometimes the head of the
greater Semiminim was void '—that '
is to say,
open or white—in which case, this note also
had a hook, to distinguish it from the minim,
^ ;
and, when this hooked form was used, the
figure which we have described above as proper
to the Greater Semiminim was used for the
Lesser one. "When black and red notes were
used together the red minim served as the
diminutive of the black one ; and the Semiminim
was called Chroma, on account of its colour. This
name was afterwards applied both to the Greater
and the Lesser Semiminim ; and hence it came
to pass that, in later times, the term Chroma
was applied indiscriminately to the crotchet
and the quaver. [See Notation.] w. s. r.
SEMIQUAVER (Lat. Semifusa ;
Ital. Semicroma,
Biscroma, Semifusa ; Germ. Sechzehntel,
whence the American term, Sixteenth Note ; Fr.
Double croche). The sixteenth part of a semibreve.
The earliest mention of the Semiquaver
occurs in the Practica Musicae of Franchinus
Gafurius, printed at Milan in 1496. It may
be found—though very rarely— in the printed
polyphonic music of the 16th century, in the
form of a black lozenge -headed note, with a
double hook, ^ or 4
; and it is manifestly