As to phosphorus, I am afraid you may never have seen any; but you may
have heard it spoken of. It is sold at the druggist's in the form of
little white sticks, about as thick as your finger; they have a
disagreeable, garlicky smell, and are obliged to be kept in jars of
water, because they seize every opportunity of taking fire; so I advise
you, if ever you do see any phosphorus, not to meddle with it--for in
burning, it sticks closely to the skin, and there is the greatest
difficulty in the world in extinguishing it, and the burns it makes
are fearful. I give you this caution, because phosphorus possesses a
very curious property, which might attract little girls. Wherever it
is rubbed, in the dark, on a door, or on a wall, it leaves a luminous
trail of a very peculiar appearance, which has been called
phosphorescent, from the name of the substance which produces it. And
in this way one can write on walls in letters of fire, to the terror
of cowards. Now, come; if you will promise to be very wise, and only
to make the experiment when your mamma is present, I will teach you
how to make phosphorescent lights without having to go to the
druggist's! There is a small quantity of phosphorus in lucifer matches,
which their garlicky smell proves. Rub them gently in the dark on a
bit of wood, and you will see a ray of light which will shine for some
moments. But mind, you must not play at that game when you are alone;
it is a dangerous amusement, and one hears every day of terrible
accidents caused by disobedient children playing with lucifer matches.
And while we are on the subject, let me warn you against putting them
into your mouth. Phosphorus is a poison, and such a powerful one that
people poison rats with bread-crumb balls in which it has been
introduced.

"Oh dear me! and that poison makes part of our teeth?"