Letters on England [34]
me about the
name I give it?"
Vortices may be called an occult quality, because their existence
was never proved. Attraction, on the contrary, is a real thing,
because its effects are demonstrated, and the proportions of it are
calculated. The cause of this cause is among the Arcana of the
Almighty.
"Precedes huc, et non amplius."
(Thus far shalt thou go, and no farther.)
LETTER XVI.--ON SIR ISAAC NEWTON'S OPTICS
The philosophers of the last age found out a new universe; and a
circumstance which made its discovery more difficult was that no one
had so much as suspected its existence. The most sage and judicious
were of opinion that it was a frantic rashness to dare so much as to
imagine that it was possible to guess the laws by which the
celestial bodies move and the manner how light acts. Galileo, by
his astronomical discoveries, Kepler, by his calculation, Descartes
(at least, in his dioptrics), and Sir Isaac Newton, in all his
works, severally saw the mechanism of the springs of the world. The
geometricians have subjected infinity to the laws of calculation.
The circulation of the blood in animals, and of the sap in
vegetables, have changed the face of Nature with regard to us. A
new kind of existence has been given to bodies in the air-pump. By
the assistance of telescopes bodies have been brought nearer to one
another. Finally, the several discoveries which Sir Isaac Newton
has made on light are equal to the boldest things which the
curiosity of man could expect after so many philosophical novelties.
Till Antonio de Dominis the rainbow was considered as an
inexplicable miracle. This philosopher guessed that it was a
necessary effect of the sun and rain. Descartes gained immortal
fame by his mathematical explication of this so natural a
phenomenon. He calculated the reflections and refractions of light
in drops of rain. And his sagacity on this occasion was at that
time looked upon as next to divine.
But what would he have said had it been proved to him that he was
mistaken in the nature of light; that he had not the least reason to
maintain that it is a globular body? That it is false to assert
that this matter, spreading itself through the whole, waits only to
be projected forward by the sun, in order to be put in action, in
like manner as a long staff acts at one end when pushed forward by
the other. That light is certainly darted by the sun; in fine, that
light is transmitted from the sun to the earth in about seven
minutes, though a cannonball, which were not to lose any of its
velocity, could not go that distance in less than twenty-five years.
How great would have been his astonishment had he been told that
light does not reflect directly by impinging against the solid parts
of bodies, that bodies are not transparent when they have large
pores, and that a man should arise who would demonstrate all these
paradoxes, and anatomise a single ray of light with more dexterity
than the ablest artist dissects a human body. This man is come.
Sir Isaac Newton has demonstrated to the eye, by the bare assistance
of the prism, that light is a composition of coloured rays, which,
being united, form white colour. A single ray is by him divided
into seven, which all fall upon a piece of linen, or a sheet of
white paper, in their order, one above the other, and at unequal
distances. The first is red, the second orange, the third yellow,
the fourth green, the fifth blue, the sixth indigo, the seventh a
violet-purple. Each of these rays, transmitted afterwards by a
hundred other prisms, will never change the colour it bears; in like
manner, as gold, when completely purged from its dross, will never
change afterwards in the crucible. As a superabundant proof that
each of these elementary rays has inherently in itself that which
forms its colour to the eye, take a small piece of yellow
name I give it?"
Vortices may be called an occult quality, because their existence
was never proved. Attraction, on the contrary, is a real thing,
because its effects are demonstrated, and the proportions of it are
calculated. The cause of this cause is among the Arcana of the
Almighty.
"Precedes huc, et non amplius."
(Thus far shalt thou go, and no farther.)
LETTER XVI.--ON SIR ISAAC NEWTON'S OPTICS
The philosophers of the last age found out a new universe; and a
circumstance which made its discovery more difficult was that no one
had so much as suspected its existence. The most sage and judicious
were of opinion that it was a frantic rashness to dare so much as to
imagine that it was possible to guess the laws by which the
celestial bodies move and the manner how light acts. Galileo, by
his astronomical discoveries, Kepler, by his calculation, Descartes
(at least, in his dioptrics), and Sir Isaac Newton, in all his
works, severally saw the mechanism of the springs of the world. The
geometricians have subjected infinity to the laws of calculation.
The circulation of the blood in animals, and of the sap in
vegetables, have changed the face of Nature with regard to us. A
new kind of existence has been given to bodies in the air-pump. By
the assistance of telescopes bodies have been brought nearer to one
another. Finally, the several discoveries which Sir Isaac Newton
has made on light are equal to the boldest things which the
curiosity of man could expect after so many philosophical novelties.
Till Antonio de Dominis the rainbow was considered as an
inexplicable miracle. This philosopher guessed that it was a
necessary effect of the sun and rain. Descartes gained immortal
fame by his mathematical explication of this so natural a
phenomenon. He calculated the reflections and refractions of light
in drops of rain. And his sagacity on this occasion was at that
time looked upon as next to divine.
But what would he have said had it been proved to him that he was
mistaken in the nature of light; that he had not the least reason to
maintain that it is a globular body? That it is false to assert
that this matter, spreading itself through the whole, waits only to
be projected forward by the sun, in order to be put in action, in
like manner as a long staff acts at one end when pushed forward by
the other. That light is certainly darted by the sun; in fine, that
light is transmitted from the sun to the earth in about seven
minutes, though a cannonball, which were not to lose any of its
velocity, could not go that distance in less than twenty-five years.
How great would have been his astonishment had he been told that
light does not reflect directly by impinging against the solid parts
of bodies, that bodies are not transparent when they have large
pores, and that a man should arise who would demonstrate all these
paradoxes, and anatomise a single ray of light with more dexterity
than the ablest artist dissects a human body. This man is come.
Sir Isaac Newton has demonstrated to the eye, by the bare assistance
of the prism, that light is a composition of coloured rays, which,
being united, form white colour. A single ray is by him divided
into seven, which all fall upon a piece of linen, or a sheet of
white paper, in their order, one above the other, and at unequal
distances. The first is red, the second orange, the third yellow,
the fourth green, the fifth blue, the sixth indigo, the seventh a
violet-purple. Each of these rays, transmitted afterwards by a
hundred other prisms, will never change the colour it bears; in like
manner, as gold, when completely purged from its dross, will never
change afterwards in the crucible. As a superabundant proof that
each of these elementary rays has inherently in itself that which
forms its colour to the eye, take a small piece of yellow