brambles. You say they are marks of fingernails,
and you set up the hypothesis that she
destroyed her child. You must accept all
consequences of that hypothesis. For anything
we know, she may have destroyed her child,
and the child in clinging to her may have
scratched her hands. What then? You are not
trying her for the murder of her child; why don't
you? As to this case, if you will have scratches,
we say that, for anything we know, you may have
accounted for them, assuming for the sake of
argument that you have not invented them?' To
sum up, sir," said Wemmick, "Mr. Jaggers was
altogether too many for the Jury, and they
gave in."

"Has she been in his service ever since?"

"Yes; but not only that," said Wemmick.
"She went into his service immediately after
her acquittal, tamed as she is now. She has
since been taught one thing and another in
the way of her duties, but she was tamed from
the beginning."

"Do you remember the sex of the child?"

"Said to have been a girl."

"You have nothing more to say to me
tonight?"

"Nothing. I got your letter and destroyed
it. Nothing."

We exchanged a cordial Good Night, and I
went home, with new matter for my thoughts,
though with no relief from the old.

RECENT DISCOVERIES CONCERNING
LIGHT.

IN the year 1666 the young Mr. Isaac Newton,
then an unknown Bachelor of Arts of the
University of Cambridge, little more than
twenty-three years of age, first made the
discovery of the compound nature of white light,
and he described this discovery a few years
afterwards, in a letter to a friend, as "in my
judgment the oddest, if not the most considerable
detection which hath hitherto been made in the
operations of nature."

Let us pause here a moment to explain clearly
what this "detection" or discovery amounted to,
premising that one of its first fruits had already
appeared (in 1609) in the construction of a
reflecting telescope. Before the publication of
Newton's researches in 1671, the sources and
nature of coloured, as distinguished from white
light had not even been the subject of a
rational conjecture. Dr. Barrow, the latest and
best authority, had described white, as being
"that which discharges a copious light equally
clear in every direction." "Black," he goes
on to state, "is that which does not emit
light at all, or which does it very sparingly.
Red is that which emits a light more clear than
usual, but interrupted by shady interstices. Blue
is that which discharges a rarefied light, as in
bodies which consist of white and black
particles, arranged alternately. Green is nearly
allied to blue. Yellow is a mixture of much
white and a little red; and purple consists of a
great deal of blue, mixed with a small portion
of red." By causing a ray of the sun's light to
pass first through a round aperture in a shutter
and then through a prism of glass, and afterwards
receiving the image on a screen in a darkened
room, Newton found that its shape was no longer
round, but oblong, and he seems to have been
the first to notice that it consisted of variously
coloured light. Every part of the ray had been
turned or bent aside, as was known to be the
result when light passes from one medium—such
as air—into another of different density, like
glass: but the image showed that the white
light was, in fact, made up of a mixture of red,
yellow, and blue rays, of which the red were
least bent and the blue most, the yellow
occupying the middle place.

It was further noticed that the coloured
image of the sun thus obtained, while retaining
the breadth that it would have had, if not
broken up into colours, was now five times as
long, and by allowing each colour in succession
to pass through a round hole, similar to the
first, and then through a second prism into
another chamber, also darkened, it was found
that the coloured image was now, as before,
bent aside, but was not altered again in shape.
It was remarked, too, that in the second, as in
the first bending or refraction, red rays were
not so much bent by the prism as the yellow,
and the yellow not so much as the blue. It
was hence concluded that each ray of white
light coming from the sun, was made up of rays
of several colours-- red, yellow, and blue being
the chief—that these simple colours were all
more or less, but each differently, bent in passing
from one transparent body to another, and
that, having been once decomposed, the various
colours were not susceptible of further change.

Newton afterwards, by various other
experiments, fully satisfied both himself and all his
contemporaries, that this view of the compound
nature of light was correct, and that, in fact, all
the marvellous beauties and effects of colour
are produced by the different proportion in
which the colour rays that together form white
light are absorbed, transmitted, or reflected
by various substances before they reach the
eye. The delicate pink reflected from a snowy
mountain at sunset is due to the slight excess
of blue and yellow rays absorbed by vapour
when the sun's light passes aslant through a
vast thickness of air; the yellow of the buttercup
results from the structure of the petals of
the flower which happen to absorb blue and red
light but reflect the remaining rays, and the
exquisite blue of the ocean and sky result from
the absorption of red and yellow rays in clear
dry air and the reflexion or transmission of the
rest, the constant alteration observed in these
respects being caused by the frequent change
that takes place in the air in reference to visible
moisture.

By very careful observations made with fine
prisms, assisted by other optical contrivances,
Dr. Wollaston first, and afterwards M. Fraunhofer,
of Munich, discovered that the oblong
image of coloured light obtained by decomposing