of one part
of hydrogen gas that will come off easily and that gives it its sour
taste, two parts of carbon, three parts of hydrogen that does not come
off so easily, and two parts of oxygen. When you put this with baking
soda, which is made of one part of the metal sodium, one part of
hydrogen, one part of carbon, and three parts of oxygen, you get water
and carbon dioxid gas and a kind of salt called sodium acetate." Or,
more briefly, "If you put baking soda with vinegar, you get water, a
gas called carbon dioxid, and a salt." You can see how much shorter
the chemist's way of writing it is.

SOME ELEMENTS YOU ALREADY KNOW. Here is a list of some elements that
you are already pretty well acquainted with. The abbreviation is put
after the name for each. This list is only for reference and need not
be learned.

Aluminum (Al)
Carbon (C) Charcoal, diamonds, graphite (the lead in a
pencil is graphite), hard coal, and soot are
all made of carbon.
Chlorine (Cl) A poison gas that was used in the war.
Copper (Cu)
Gold (Au)
Hydrogen (H) The lightest gas in the world; you got it from
water in the last experiment and will get it
from an acid in the next.
Iodine (I) It is a solid; what you use is iodine dissolved
in alcohol.
Iron (Fe)
Lead (Pb)
Mercury (Hg) This is another name for quicksilver.
Nickel (Ni)
Nitrogen (N) About four fifths of the air is pure nitrogen.
Oxygen (O) This is the part of the air we use in breathing.
You got some out of water, and you will
have it to deal with in another experiment.
Phosphorus (P) Phosphorus makes matches glow in the dark,
and it makes them strike easily.
Platinum (Pt)
Radium (Ra)
Silver (Ag)
Sodium (Na) You are not acquainted with sodium by itself,
but when it is combined with the poison
gas, chlorine, it makes ordinary table salt.
Sulfur (S)
Tin (Sn)
Zinc (Zn)

For the rest of the elements you can refer to any textbook on
chemistry.

HOW ELEMENTS HIDE IN COMPOUNDS. One strange thing about an element
is that it can hide so completely, by combining with another
element, that you would never know it