, 1897-04-03
FIRST PEN. LECTURE.
Prot. Ridgaway Upon Magnetism and
Electricity.

IN OF the most practical and interest
ing lectures OF the year a delivered by
Prof. Ridgaway at the state penitentiary
yesterday afternoon. The prisoners
greatly enjoyed the unwonted treat and
several times broke out into ripples OF
laughter and enthusiastic applause.
The professor was in one Of his happiest
moods, and his auditors, closely con-
fined as they have been during the re-
cent storm, doubly appreciated the talk.
Prof. Ridgaway began by stating that
ii was difficult for him to lecture 30 as
to interest all, as some Of his audience
probably understood electricity better
than he and others possibly knew moth
ing Of 1t. He would, therefore. begin
with the very foundation Of his subject,
and hope that those who were acquaint-
ed with it, would pardon the old story.
He took up the subject of magnetism
first, and after exhibiting a piece Of iron
ore magnetised by earth currents, gave a
short history Of the discovery of the
powers Of load-stone. Next the profess
sor took up a piece OF steel, which had
become a permanent magnate by being
rubbed with a natural magnet and show
ed how this could be done. He further
demonstrated the fact that iron in the
same situation would become Temperate
ly m%agnetized, and gave the prevailing
theory OF the reason for the difference
between the W substances.
The compass. which has utilized the
principal Of magnetism, was his next
topic. This he illustrated very fully,
telling Of the declination Of the compass
in various parts of this country and
showing that the proverb "as true as the
needle to the pole is no as accurate as
generally supposed.
The matter Of b~ar-magnates and some
very pat illustrations of the connection
between magnetism and electricity were
then taken up. In connection with this
the professor explained the use OF the
tangent galvanOmeter and other tests,
and the meaning Of the various units,
ohm, ampere, volt, ETC., and several 9TH
er things Of importance in general read
ing. After this. the varieties Of the
helix were brought to the attention of
the audience, eliminating with the
Ruhmkof coil and some demonstra-
tons OF electric light. The professor
here gave exhibitions of electricity pass
ed through various Geissler and Crookes
tubes. The three aurora tubes came out
especially fine. although the light was
not as beautiful as at night. The prin-
ciple here involved was shown to be
probably the same as that known in the
rare atmoepheres Of the arctic regions
as the aurora lights" Some smaller
Crookes tubes filled with colored liquids
and one tube with calx-spar composed
the last Nominations. Then to CON
clude with, Prot. Ridgaway explained to
his audience the principle Of the X-rays,
showed them the tube and little box COW
cred at the back with tungstate Of cal
cium, and gave a short account Of the
powers Of Roentgen's discovery. He re-
GREETED that the condition of his tubes
and the light Of the room prevented his
illustrating the point more fully.
He then thanked his hearers for their
attention and nj greeted with the deaf
ening applause of 10 pairs Of hands.
The audience seemed an intelligent one
in every way. and many expressed their
gratitude to the Rev. j. W. Taylor, who
afterward visited them.
1t surprised many visitors to the Chi
cago worlds fair to find that of all the
blood-purfiers, Ayers Sarsaparilla was
the only one On exhibition. The reason
is that Ayers Sarsaparilla Is a standard
remedy, and not a patent medicine, OF
secret nostrum.
TWO STOCKS COMBINED.
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