St. Paul daily globe. [volume] (Saint Paul, Minn.) 1884-1896, 1886-01-16
PLAIN TALKS.
Lights--OId and New, illustrated
Lecture by Prof. Dodge.

Last evening the third lecture in the
series of Plain Talks for Plain People was
given by Prof Dodge of the state university
before fair number of interested listeners
at Harrison hall. The speaker was intro
duced in few complimentary words by
Rev. James McGOlrick, who has inaugu-
rated this practical method of cheap instruc-
ton for the people of his parish and all
others who desire to attend the lectures.
The lecturer began by referring to the sim
pie light of the tallow candle. the chemistry
of which he explained by experiment He
next spoke of gas, which has been in
use for seventy-fve years. and Of petroleum
w hich has been in use for a quarter of
century. Then came kerosene light which
came into use about the date of our civil
war. The simplest kind of gas flame is
that of hydrogen gas which is composed of
zinc, water and muriatic acid. The name
by which it is sometimes known is 1.-THE
philosophers candle"
Marsh gas or fire damp was next spoken
of and produced and lighted, the flame be-
ing brighter than the hydrogen flame. but
still not good enough for Illuminating pur-
poses. Olefant gas was next introduced,
the elements entering into its composition
being bicarburetted hydrogen containing one
part of hydrogen to six of carbon, and it
burns with twice the brilliancy of fire
damp on account of having twice the
quantity of carbon.
INcANDEsCENT LIGHTS.
Gas containing carbon becomes incandes-
cent as soon as lighted and the more carbon
in the gas the more SCOT is produced in the
! flame. An illustration of incandeScence
was given at this point and twas produced
| by pouring particles of carbon into the
| flame. 1t is not necessary that carbon
should be always used for the production of
incandeScence; other substances, such as
chalk, will produce better light. Calcium
| light came next under consideration. it be-
ing invented by Drummond in 1925. Its
constituent elements are hydrogen, oxygen
and lime, and when burning it has a tenn
perature of ), 0O0o. A platinum wire in
troduced into the flame ofhydrogen also pro-
duced incandescence. as well as a magnetism
| lamp in the form of clock. which requires
| to be wound up, and which then gives very
| strong light. This lamp is used in subter-
ranean and other dark places for photo
graphic purposes. The use of the mag
nesium light is extending in Europe. 1t
produces smoke which is nOn-posonous,
but is somewhat Objectionable. Another
substance when combined with hydrogen
made splendid light, viz. gasoline. Here
| the professor conveyed lne hydrogen 10 tne
gasoline by means of a tube connecting with
the burner. and produced fine light, which
he said was too expensive for ordinary pur-
poses. He then produced water gas. which
is of pale blue color, and is a mixture of
carbumeted oxide and hydrogen. He then
passed it through bottle contain
ing gasoline, thus producing a very
good light, but he said no
practical use could be made of it. He
passed on to the explanation of alcohol
lamps. spirits of turpentine campfire OF
burning fluid, the last of which he pro-
nounced dangerous substance because of
its infiammatOry nature. After showing
how candle contains gas and oil. or is IAN
oil and gas factory" as he said. he passed
on to electricity, and gave several expert
ments with small battery. Edison's in
condescent lamp and the arch electric light
were produced. and reference was made TO
Edison, Farraday, HUMPHREY, Davy, Stew
enson and other scientific men. which proved
quite interesting. A vote of thanks was
rendered the lecturer for his very interesting
talk, which was adapted TO plain people.