little better than "strolling players," who are
very vagabonds in the eyes of a polished
Chinese.

MAGNESIAN LIGHT.

How wonderfully, in these later days, common
worthless out-of-the-way unthought-of
things are, little by little, brought into use and
made to render service! Dyeing, perfumery,
confectionery, the textile and other arts, find
resources where our forefathers found either
rubbish only, or very frequently found nothing
at all, for the good reason that that special
article did not yet exist. In the same way,
many scientific discoveries which, at the outset,
were regarded as marvels, merely good to
interest philosophers and supply harmless
amusement for speculative theorists, are now
beginning to bear their fruit, and to confirm the
adage that knowlege is power.

For thousands of years, the old-fashioned
metals, as gold, silver, iron, lead, have been
familiarly known, without any one's suspecting
that their list might be extensible. Transmutation
of the one into the other—of the baser
into the more precious kinds—was deemed as
practicable and feasible as it was desirable to
effect. Nobody dreamed, for ages after ages, of
discovering, disinterring, picking out new
metals which had lain hidden under a complete
disguise ever since the world began. Many of
us are old enough to remember the sensation
produced by Sir Humphry Davy's discovery of
the metallic base of certain alkaline earths, and
the probable consequence that all such earths
were derived from metals. It was a curious
fact, well worthy of notice and remembrance,
that lime is the oxide, that is to say the rust, of
an actual metal called calcium; soda of another,
sodium; potash of another, potassium; and so
on. But little use was made of these new
metallic acquisitions. Their lightness, their
softness, their extreme readiness to return to the
earthy state, caused them to be regarded rather
as specimens to be kept under bell-glasses, or in
any other way best suited to preserve them,
than as agents and tools to assist the wants of
daily life. Except for the striking experiment
of setting fire to a lump of potassium, by throwing
it on the surface of a pan of water, samples
of the new metals were hardly even seen beyond
the walls of the chemist's laboratory, or out of
the hands of the initiated. What proportion of
our readers have ever set eyes on a morsel of
metallic sodium or calcium?

Lately, however, one new metal has made
itself conspicuous in the world. Aluminium, the
metal which is the mother of clay, started with
perhaps too brilliant a promise. Its beauty was
exaggerated; of its utility, it would be unfair to
give an unfavourable opinion at the present early
stage of its existence. If the jeweller and his
customers feel disappointment, the useful arts
may turn its peculiar qualities to advantage.
Its lightness is remarkable, and that property is
a merit, even for purposes of ornamentation;
for it enables an operatic heroine to wear a
complete suit of armour, and to sing in it too,
without sinking under the weight.

There is an earth, magnesia, with which most
of us are acquainted from childhood, our
mammas having caused us to swallow it as
medicine. Later in life, we may have resorted
to it as a remedy for heartburn, or, combined
with its cousin, Epsom salts, as an anti-podagric
purgative, an antidote to gout. Magnesia also
affords a useful remedy in cases of poisoning by
mineral acids, as vitriol, when it can be
administered internally shortly after the swallowing of
the caustic liquid. It takes away all its corrosive
strength, and transforms it into a saline
compound which no longer possesses poisonous
properties. Some invalids, however, abuse
magnesia, taking too much of it, and too frequently.
Magnesia, indulged in at this rate, produces
intestinal concretions of greater or less volume.
In one such patient, there was found, after
death, a mass of hardened magnesia weighing
nearly six pounds.

Magnesia, too, is the rust of a metal,
magnesium, which, although well known to exist,
has hitherto existed in comparative obscurity,
without exciting the world's attention. It is
never found naturally in the metallic state, and
was first so attained, in 1829, by M. Bussy. It
is not twice as heavy as water. Its specific
gravity is 1.743, that of water (at its greatest
density) being 1.000.

As an earth, magnesia is variously regarded
by agriculturists, most of them looking down
upon it askance; they may therefore rejoice that
it is not very generally nor widely spread.
Perhaps its demerits may be more justly charged
against it when applied burnt, as manure, than
when existing on the spot as natural earth.
The presence of magnesia in limestone has been
considered pernicious to vegetation when burnt
into lime. It had long been known to farmers
in the neighbourhood of Doncaster and other
parts of Yorkshire, Derby, and Nottingham, that
lime made from a peculiar species of limestone
injured their crops. Experiments on this
limestone, made by Mr. Tennant, showed that it
contained magnesia. On mixing pure calcined
magnesia with earth in which he sowed
different kinds of seeds, he found that they either
died or vegetated very imperfectly; he therefore
came to the conclusion that its effects were
prejudicial. This is thought to have been
occasioned by its retaining its caustic quality longer
than pure lime. From experiments made by
Sir Humphry Davy and other chemists, it may
be assumed that although, when calcined as
lime, it may become pernicious if laid on the
land in too large quantities, yet that, in its mild
state, it is a useful constituent of soils. One of
the most fertile parts of Cornwall, in the
neighbourhood of the Lizard, is a district which
abounds in magnesian earth.

During the last few months, in Paris,
magnesium has started into celebrity—made itself a
lion, in short. At scientific conferences and