An atom of H is the chemist’s unit. This is a colorless, odorless,
tasteless gas, fourteen times lighter than air. When burned it produces a
more intense heat than any other substance. Iron burns in its flame like
paper. When united with O, and a piece of lime is inserted in the flame,
the latter becomes exceedingly brilliant, forming the Drummond light,
which has been seen at the distance of one hundred miles in the daytime.
So diffusive is H that if a sheet of paper or gold-leaf be placed over an
escaping jet of the gas, it will pass directly through the paper, and may
be lighted on the upper side. H is easily prepared, and many interesting
experiments may be performed with it, some of which it may be well to
mention. Take up on a pointed wire or needle or with tweezers, a piece of
the metal sodium, quickly insert it under a tube filled with water and
invert in a glass of water; the sodium will at once take the O and leave
the H to displace the water in the tube. Remove the tube, still holding
it with opening downward; apply lighted match and a slight explosion will
follow. What two properties of H have you shown by your experiment?
[Illustration: COLLECTING HYDROGEN EVOLVED FROM WATER BY SODIUM.]
Take a bottle holding one or two pints, fit a cork to it, through which
pass a glass or metallic tube, the end of which is drawn out so as to
leave a small aperture at the top. Place in the bottle a few pieces of
zinc, and some sulphuric acid, diluted with water, in the proportions
of one part of acid to six of water, then insert the cork. You will
immediately see bubbles of H rising. The explanation of this is as
follows: The zinc takes O from the water, thus liberating H; the O forms
an oxide on the surface of the metal, which would prevent further action,
did not the acid dissolve the oxide, thus leaving a fresh surface to
take the O, and continue liberating H until the metal disappears. After
the H has been forming for two or three minutes, hold over the tube an
inverted tumbler for a moment, remove the tumbler and then apply a match
to the contents of tumbler. When the bottle has become _filled_ with H
you can light the gas at the top of the tube, and thus have a steady
flame. Be careful not to attempt to ignite the gas until all of the
air has been forced out of the bottle, as air mixed with H produces an
explosive mixture. In the intense heat of the faint flame you can melt
metals or glass. By placing a larger glass tube, open at both ends, over
the flame, you may be able to produce the celebrated acoustic tones,
varying in pitch and intensity with the size and length of the tube used.
A hydrogen gun can easily be made by taking a tin tube five or six inches
long (closed at one end), from one half inch to an inch in diameter; make
a small aperture near the closed end; then invert the tube for a moment
over the escaping H, keeping the small hole closed with the finger, place
a cork in the open end, and apply a match to the hole. The cork will be
forced out with a loud explosion. What compound is always produced when H
is burned? Let us see. Invert a cold, dry tumbler over a burning jet, and
you will always observe moisture gathering on its surface. Another pretty
experiment may be performed with H by inserting the stem of a common
clay pipe in a piece of rubber tubing, slip the other end of the tubing
over the gas jet, prepare some strong soap suds, and with a little care
you can blow beautiful soap bubbles with your pipe, which, by a skillful
movement may be detached, and they will rise in the air like miniature
balloons; by placing a burning match under them they will explode. Strike
a bell in a large jar filled with H, and it has a squeaky sound. Our
whole art and science of music would be changed if H should be mixed with
the air to any great extent.
Nicely balance a flask or jar containing air; fill the same flask with H,
and the beam will at once be seen to rise.
Let us find the antipodes of weight. Iridium, hammered to increase its
density, is twenty-three times heavier than water; water is about eight
hundred times heavier than air, and air is fourteen times heavier than H:
23×800×14=257,600; that is, one quart of Ir would balance 257,600 quarts
of H.