New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1872-12-23
NETWORK DAILY TRIBUNE. MONDAY. DECEMBER %. 1872

may be totally reflected and the other not an ops yo
eian named Nico crystal OF Iceland spar IA Two
10 certain hd aeSUP Sy nsas ba surface
Of union being inclined TO the beam trayerslpg me
Tefraeted was totally reflected by the balsam, While
the extraordinary ray was permitted TO pass on inc M
venon Of tie NcOs prism great step IN pracucal
optics and quite recently such prisms have been con-
slructed OF size which enables audiences NE .nd
present TO witness the chromatic phonomena on polou
ght TO degree altogether unattainable short time ago.
Tie two psns here before yon belong 20 my eACUs
ured by Mr. Ladd. 1have with me another par on very
noble prisns, still larger than these ya aTr
by Mr.. Browning, wnU mas Ralneu 50 w eIu
mered areputation In the CONSTRUCTOR OF sectoseoP''
THE VIVID coLoRs OF PoLARIzED LIGHT
These two NcOl's prisms play the same part as tho
crystals OF ourmallne Placed with their oirecuons VI
vibration parallel the light passes through both "hen
these directions crossed the light is quencheu IN
PRODUCING a film of mica between the prisms the hkH'
ia In part restored But notice, when the MN OF oa
IL thin you have not only light but cOloIeu hkn, 81
work some time 10 come will be the exainlnadio,, o.
these colors With tlds VIEW Will take represents
tive crystal easily dealt with that Is the eays
gypsum or selenite which Is ery5tazou tlL nate
lime Between the crossed hcols place IIick Pa.e s
of this CRYSTALS like the mica. 1t restores the light put
It produces no color win my penae ho tSns the The
prisms; its image the screen glOWs WIN tne cnssI
coors Turning the prism IN 'front.' these eSDTs n
vibrating sections OF the prislns are parallel Yyd
eoOrs again appear but these coOrs are Complementary
20 the former ones.
The magnlncence Of these polarlzed coors with the
full light Of the voltac is quite indescrbable Even
TO those who have the finest OF such effects through
the lenses OF poarlscope these screen images were
delicious surprise. Nothing but sunset sky can com
pare with these splendors.l
Some patches the splinter appear o'one color some
OF another these differences being due to the derent
thicknesses OF the film. III the thickness pc UNIFORM
the color uniform. Here. for instance, stellar
shape every Ozenge OF the star being hn OF gypsum
OF uniform thickness Each lOzenge you observe SHOWS
brilliant uniform color. or course IL Is easy by snap
ing our films represent flowers or other objects,
10 exhibit such objects in coors unatalnaOle Dy art
Here, for example, Is specimen VI heartsease Ihe
cOOrs which you might safely defy the artist 10 repro
duce. BY turning the front kcol 900 round we pass
through cOloress phase to series OF cOois SomPe-
mentary TO tho former ones Here, Tor example Is
rose on twig red flower and green leaves turning
the prism 900 round, obtain green hover ana req
leaves
THESE fading and flushing flowers alternating In COM
Elementary tnts curiousy beautiful The lecturer
humorously apologzed for the abnormal spectacle OF
green rose with red leaves Some wag In the audience
suggested in stage-whisper, that 1t was all right
merely a cabbagerose.1
All these wonderful chromatlc effects have definite
causes In the motions OF tho ether the p
cipe OF Interference duly applied and Interpreted
eX plains them all; and II you give me your patence
SHALL far as 1t is necessary, develop tue CAUSES VI
these effects in our next lecture.