says the advertisement in the Times,
with the hope of inducing you to purchase
a patent self-cleansing charcoal-filter. Don't
see them, unless you are both strong-minded
and strong-stomached; that's my advice.
And, while I am giving it, in steps Noakes
(who has heard of Styles's scientific acquisition)
with a sample, in a wine-glass, from his
own private pump. At the bottom of the glass
a tiny milk-white speck glides along with slow
but steady motion. With gentle skill it
is transferred with a drop of water to the
meniscus-glass of the microscope, placed in
the stand, peeped at with a low power as a
transparent object—and what is beheld?
Something very like a whale of the spermaceti
species, protruding its huge lips, and
glaring with a pair of coal-black eyes. Its
substance is an elastic gelatinous blubber
composed of grains, which are visibly distinct
like the berries in a bunch of grapes. Its
fleshy, granulated mass heaves and sinks,
dilates and contracts, at every motion. But
it has clouded the water by a voluntary act.
Let us strand our whale on an ebony shore
by the agency of a pin, to see how he will
behave on dry land. He is burst—he is
poured out like a curdled fluid—he is dried
up—he is gone! Nothing is left of him but
a morsel of film scarcely visible to the naked
eye.

Little Tom is chasing a white cabbage-butterfly
on the grass-plot. It is too much
for him; it darts away between a laurel and
a rose-bush. No; he has it; it has been
stopped by the wide-spread net of a large
garden-spider—the diadem. Stay a moment,
Tom, before you brush the web utterly away.
We will catch a portion of the tissue on this
slip of window glass. It makes a nice little
tailor's pattern of real gossamer cloth for
summer use. But, instead of the threads
crossing each other at right angles like the
warp and the woof of human looms, there is a
framework of threads like the spokes of a
wheel, across which other threads are woven
round and round. Look; the power of the
object-glass is high, and we have got into
the field of view a point where the threads
cross. But observe, the radiating thread is
plain and smooth, like a simple iron wire;
while the concentric threads are studded at
intervals with transparent beads of different
sizes, one or two little ones intervening
between each large one, like artificial necklaces
of pearls. They are chaplets and rosaries
on which the flies may say their prayers
before they receive the finishing stroke from
their executioner, the diadem-spider. It is
the viscid globules which appear to give to
these threads their peculiarly adhesive
character. If you throw dust on a circular
spider's web, you may observe that it
adheres to the threads which are spirally
disposed, but not to those that radiate from
the centre to the circumference, because the
former only are strung with gummy pearls.
You now know how to distinguish with the
microscope the thread of the warp in a
spider's web, from the thread of the woof.

The butterfly flutters in Tom's little fingers.
Let it flutter—hold against it another slip of
glass. The slip is covered with white dust.
Let us submit that to the searching power;
and, lo! we have a collection of scales or
feathers, with the quill as distinctly visible
as that of the pen I now hold in my
hand. Some are broad and flat, with
deep-cut notches at their end, semi-transparent,
as if made of gelatine, and clearly
marked with longitudinal stripes—proof that
the instrument is not a bad one—others are
more taper in their proportions, opaline in
texture, mottled with cloudy spots, and
terminate very curiously in a tuft of bristles,
each of which seems to have a little bead at
its tip end. What can be the use of them?
Feather-scales terminating in a pencil of hairs
like the stamens of flowers? But, the butterfly
is stark dead—Tom has pinched its body so
tight to prevent its escape. It is much too
enormous a creature to be looked at entire
with a microscope; we must cut up its carcase,
as a butcher does an ox, and serve it out
piecemeal. Then we ascertain that its horns
or antennæ are covered with scales; they are
elegant shafts, like the trunks of young
palmtrees. We have rubbed off some of the scales
in our clumsy dissection—they are strewn
on the slip of glass beside their parent stem;
and we may remark that each scale has at its
top a single notch cut out of it like the letter
V, or the wedge of cake which a schoolboy
would produce with two strokes of the knife,
if allowed to help himself. Our butterfly's
eyes are composite, made up of eyelets to be
counted—or left uncounted—by hundreds.
His feet have some resemblance to a hand,
which you might imagine to be mainly
composed of a couple of broad miller's-thumbs;
but the wonder of wonders is his elaborate
proboscis, folding up spirally, composed of an
infinity of corkscrew vessels, and furnished
with elastic suckers and pumps. All this
we behold as clearly, though bit by bit, as
we see that a centenarian oak consists of
roots, trunk, branches, and leaves. One of
these days some ingenious artist in taxidermy
might treat us to a model of the
cabbage-butterfly, putting together its parts as was
done with the model of the dodo, only on a
highly magnified scale. Nothing but such a
property butterfly as this (to use theatrical
phraseology), with every plumelet as visible
as those on a turkey-cock, can give us an
idea of the stately presence of a papillionaceous
dandy as he appears in the eyes of his
fellow lepidopteræ.

Dust is commonly spoken of as a precise,
unvarying, specific thing; the same under all
circumstances and in all places. Dust is a
nuisance to be despised, to be wiped away, or
where not, to have the word Slut reproachfully
traced on it with a finger-tip. But