The Stourbridge Observer, Cradley Heath, Halesowen & District Chronicle.
Stourbridge, West Midlands, England, 1879-01-04 00:00:00

A SOAP BUBBLE.

On Saturday afternoon, in London, Profcs,or Dewar gave
the first of a series of Christmas lectures on "A Soap
Bubble," at the Royal Institution, Albermarle s'rett. The
lectures are specially intended for a juvenile audience, but
half of those who attended on the present occasion were
certainly considerably removed from that category.
The Professor began by observing that there were
very few of his auditors who bad not at some time or
other indulged in the blowing of soap-bubbles.
He wanted them to go back to their childhood—
not, however, to play, but to think. They all
remembered how a soap bubble was made; water,
soap, and a pipe were brought into requisi-
tion, and then the flteting, elastic, and beautifully
coloured bubble was cast adrift. The lecturer here
made a bubble, somewhat after the old fashion, using
a glass air-pipe instead of the breath, and ended by
depositing it on a iron ring in a square glass box.
Placing a piece of cardboard on an opening in the
upper side of the box, so as to exclude the air, he by
this means succeeded in preserving the bubble until he
had exhibited on the screen all the changes in its
colours, Gradually the bubble assumed the most
beautiful and delicate hues, and when placed under a
limelight looked like a transparent globe of the most
dazzling and varied tints. The:. ecturer assured the
audience it was quite possible to keep the bubble
thus imprisoned for hours if it were made of the
right material. He then proceeded to explain
the nature of the soap, air, and water the
ingredients composing the bubble. Soap, he
said, was a sakt, though made from fatty oils.
These eils, when treated to an infusion of a certain
alkali, were broken up and afterwards combined, and
made the substances called soap. The Professor
illustrated this by an experiment. He poured some
fatty substances into a dish, added the alkali, and in
about forty seconds had a piece of solid soap, having
previously strained off the excessive fluid. The best
substance, however, with which to make a soap bub-
ble was that commonly known as glycerine, which
was obtained from stearin(' and olein, the chemical
names of the common fats. It was necessary
that the glycerine should be carefully added,
and in proper proportions, for this was a most
remarkable agent, inasmuch as dynamite and gun-
cotton, the most terrible of all explosives, were pro-
duced from glycerine. This same substance had the
curious property of absorbing ws,ter from the air con-
tained in the bubble, and so kept the bubble from
breaking. The professor next practically illustrated
the separation of metals from salts, raising burning
metal globules with an electric rod from'a crucible,
in which both the metals and the salts were melted.
He also showed, by means of a number of connected
glass tubes, the combustion of a cane, and how
everything that came from the candle was seized and
separated—in other words, resolved into its primary
elements. Having explained the nature of air, the
lecturer concluded by a dtscription of the properties
of water, and, illustrating the mode in which the
latter may be tested, had a ray of light passed through
a tnbe containing distilled water, the reflection pass-
ing through a powerful magnifier at the end of the
tube on to the screen. The lecture, which was en-
tirely free from scientific phraseology, and therefore
all the more easily understood, was frequently inter-
rupted by applause.