124 Chapter 8
men are diversely affected by the same objects according to the diversity of their constitu-
tion. To them of Java pepper is cold. ”^10
Among the modes, Newton puts in the highest place the Mixolydian, which “ excels ”
the Dorian he places second (see figure 3.4); all the other modes he considers even more
“ diminished ” in “ sweetness. ” Here Newton seems to follow contemporary trends in music
theory, which gradually came to prefer what we call the major mode (which is essentially
Mixolydian with a raised seventh, F ᅊ ) over the church modes, among which Dorian was
the first in the usual order. In his final sections, Newton also notes that “ Tis usual to pass
from one mode to another in the midst of a song, ” the practice of modulation we considered
in chapter 3: what during the sixteenth century was rare became common in Newton ’ s
time, during the same period when the formerly unimaginable motion of the Earth became
widely accepted.^11
A decade after “ Of Musick, ” Newton ’ s analogy between optics and music came forward
in his comparison of the spectral colors to the seven notes of the diatonic scale, first pre-
sented publicly in his second letter on light and colors for the Royal Society (1675).^12
There, Newton observes that as vibrating bodies excite sounds of various tones, so does
light excite the optic nerve,much after the manner, that in the sense of hearing, nature makes use of aereal vibrations of several
bignesses to generate sounds of divers tones; for the analogy of nature is to be observed. And further,
as the harmony and discord of sounds proceed from the proportions of the aereal vibrations, so may
the harmony of some colours, as of golden and blue, and the discord of others, as of red and blue,
proceed from the proportions of the aethereal. And possibly colour may be distinguished into its
principal degrees, red, orange, yellow, green, blue, indigo, and deep violet, on the same ground, that
sound within an eighth [octave] is graduated into tones.^13Newton goes on to describe how he had projected prismatic colors in a dark room and
asked “ a friend to draw with a pencil lines cross the image, or pillar of colours, where
every one of the several aforenamed colours was most full and brisk, and also where he
judged the truest confines of them to be. And this I did partly because my own eyes are
not very critical in distinguishing colours, partly because another, to whom I had not com-
municated my thoughts about this matter, could have nothing but his eyes to determine
his fancy in making those marks. ” This notably solitary and secretive worker used “ a
friend ” to check his own lack of critical judgment about colors, though Newton never
made a similar acknowledgment about his sense of pitch; in his account, the tones within
an octave seem a better established frame of reference against which he judges the vagaries
of color perception. Though Newton acknowledges that “ the just confines of the colours
are hard to be assigned, because they pass into one another by insensible gradation, ” he
notes that “ this observation we repeated divers times ” and that “ the differences of the
observations were but little, especially toward the red end. ” By “ taking means between
those differences ” Newton judged that the length of the whole image “ was divided in about