Year: 1869

LECTURE ON THE PHOTOMETER by DIR. j. OGDEN


D0REMUS.


Prof. j. Ogden Doremus delivered the ninth
lecture OF the scientific course before tho American In
Stituc last evening" at steInway Hail. lie said Ladies
and Gentlemen" In the beginning God created
the heavens and the EARTH and they were without
ana Vod; and darkness upon the face OF the pro-
found. What pen shall describe what tongue shall tell
what human Imagination conceive OF that tide OF glory
and splendor which undulated throughout immcnsty
when God said, Let light be-" and light was such IL
tho most beautiful and terse description offered in THAT
word Of God which the Christian, leaves his anchor
age earth, blesses the Almighty that he can pillow
his head upon To tell the story Of the first light which
dawned upon the universe OF God, beyond the power
Of man. To tell indeed what has been discovered con
cernng 1t would extend beyond the short time allotted to
lecture 1hat hght moves through space with the i'm
mense velocity Of nearly 100000 miles IN second Of time;
that when We look at the sun We gaze at
the light that parted from 1t minutes ago. that when
look at the stars ono Is so near MS but that three and
quarter years nave eapsed during he pnSsage OF that
mysterious iatuence; ana Whcn We look uD on such
beautiful coudlcss night as thls evening ana sec me
send US light which started on It's march long before we
bOrD and In eases, ages before our race
existing upon this word.all this is known to modern
science After some further preliminary remarks, Prof
Dorcmus said that he should not attempt IN tins lecture
simple points: /. How do we produce lightl 2. OF
what is light cOnstuedl How do We measure 1t Z
lie the production OF light aud heat by various
beautiful OBSERVATION-DISCLOSURES the metal antmOny in
OF the air. potassium piece OF ice; zinc I'm oxygen and
melting and burning iron before the oxyydrogen blow





and OF great heat and briancy. But said he. 1T IA not
enough produce heat III the product OF tho combus
ti0n is only gasas he showed with tho hame OF com
mon Bunson burner intense heat but very little light Is
produced To change the heat to light we must have
solid body 20 give out the light by heating bit OF lime
I'm common street burned with jet OF oxygen the
brilliant calcium light is produced He showed the same
light with small pieces OF compressed mngnesia heated
the same way He also produced similar brilliant light
by burning the metal magnesium IN the air. Bat, sald
the lecturer produce light by means which far
surpasses any Of them. He then exhibited the electric
light produced by the and OF battery Of $50 jars such as
used I'm electric elegraphng BY using points OF
brass copper aud ron light OF different coors, and de-
grces Of Intensity produced but with points VI char
liancy, almost equal TO tho light OF the sun.
He also showed beautiful revolving lights of different
cOl0s, produced sparks from the electric machine
passing through partial vacuums Of different gases
OF degrees OF heat-its chemical acOn-or Its illum.
mating power. lie exhibited two kinds OF PhOOmeters
for measuring the illuminating power OF hgh-one, that
of Buusen tle one commonly uscdand the other large
screc on which the shadows produced successfully
Oblitcraed by the light OF candle The gasburner tho
DrummOnd light the Magnesium light, were successfully
obscured and oblitcratcd, I'LL tho moro bril-
liant electric light obliteratcd them ALL
The lecture was full OF valuable instruction, and his
pgYlnentl as brilliant and beautiful his theme. But
perhaps the most Interesting OF all was what no said or
passing superhcated steam and manganato OF Soda and
Of the great Improvement this will effect I'm lighting our
streets public buildings, aud light houses He said that
the improvement wOud effect saving OF 10 10 40 per
cent and would render the air Impure by burning up
its oxygen 1ug IL with n0Xous gases, ana Dy us mar
mOn6us blending OF the different coOrs would furnish
more beautiful aud perfect light resembling that OF tho
IL Is already used IN Paris ana soon Will Do IN New
York some OF our heaviest capitalists having taken IL In
hand with burners lighted In tins way he illuminated
the entire hall most brilliantly the large number OF com
mon gas burners pang before slcky
was greeted by the delighted audience with tho greatest