y any one, by the method above
described; that is by laying a coloured circle of paper or silk on a
sheet of white paper, and inspecting it some time with steady eyes,
and then either gently closing them, or removing them on another part
of the white paper, and the ocular spectrum or opposite colour becomes
visible in the eye.

Sir Isaac Newton has observed, that the breadths of the seven primary
colours in the sun's image refracted by a prism, are proportioned to
the seven musical notes of the gamut; or to the intervals of the eight
sounds contained in an octave.

From this curious coincidence, it has been proposed to produce a
luminous music, consisting of successions or combinations of colours,
analogous to a tune in respect to the proportions above mentioned.
This might be performed by a strong light, made by means of Mr.
Argand's lamps, passing through coloured glasses, and falling on a
defined part of the wall, with moveable blinds before them, which
might communicate with the keys of a harpsichord, and thus produce at
the same time visible and audible music in unison with each other.

Now as the pleasure we receive from the sensation of melodious notes,
independent of musical time, and of the previous associations of
agreeable ideas with them, must arise from our hearing some
proportions of sounds after others more easily, distinctly, or
agreeably; and as there is a coincidence between the proportions of
the primary colours, and the primary sounds, if they may be so called;
the same laws must probably govern the sensations of both. In this
circumstance therefore consists the sisterhood of Music and Painting;
and hence they claim a right to borrow metaphors from each other:
musicians to speak of the brilliancy of sounds, and the light and
shade of a concerto; and painters of the harmony of colours, and the
tone of a picture.

This source of pleasure received from the melodious succession of
colours or of sounds must not be confounded with the pleasure received
from the repetition of them explained above, though the repetition, or
division of musical notes into bars, so as to produce common or triple
time, contributes much to the pleasure of music; but in viewing a
fixed landscape nothing like musical time exists; and the pleasure
received therefore from certain successions of colours must depend
only on the more easy or distinct action of the retina in perceiving
some colours after others, or in their vicinit