The Red Cloud chief., 1878-03-28
E,slstiss In PhstsgrsDhy.


That chemical decomposition. Is AT.
fected by the solar rays. appears 20 have
tsen known N the ancient Egyptians
They are suppos~d n have bc.n fsmil.
lar with the action II ligh, on silver. by
which I, 10 blackcned and picture. made.
The Arst smtbcntic record 81 picture.
made by solar agency Is found In Coop.
err. RAtioeai Reerestiops." published
In England In l77t An asOuni " CIV.
en- of the marking ~ bottIe- rs the az
ton IN silver salts. Schielc n.xt eSpe-
rimcptcd on the result ~ exposing to
light paper made sensitive with salts VI
silver. he recorded tina, the drcompo.
sition ~ blarkcning was most strongly
marked In the violet rays ~ light. and
next In orange and yellow. IT, di~ov-
cred that the most rcfrAngiblc part NJ
the air l. that which takes pictures.
Bolton and Watt, la their labors Ia per.
feet the steam engine ~ Soho, probably
produced the first genuine sun-pictnrcs.
They were followed by Sir Humphrey
Dayy and Wedgswood. whO prepared
sensitive paper, and on this placed fern
and other grasses. When exposed "a
light. the parts not covered were black
encd. The immag. NJ the fern ap-
peared In white. but the inventors new
sr discovered = way Ia M the picture.
When exposed Ia light I, soon turned
Ia black.
The experiments Of Nicpce. from
1914 to 1927, led 4 the invention Of a
crude hcliotypc process. by the use 81
resin and bitumen His pictures we're
poor. but they induced Daguerre, In
1924. 10 Join in experimenting with him.
In 1889 Daguerrc's process was given
to the world, When the news was first
brought 10 this country. IL was regard
I'll rs incredible. Only four years be-
fore. the public hal been hoaxcd by "A
clcverly-writtcn account, In a New York
paper, II what Lord Ross had discoy.
cred In the moo through his big tclc-
scope at the Cape Of Good Hope. A
very graphic account Of the moons in
habitants WAS given. and the article
gained In reality from u skilful use Of
scientific terms. II was several months
before the great moon hoax' was cx-
plodcd. SO people were naturally skep-
teal about Dsgucrre's astonishing sto-
~. One man In this city believed it
that was DR.. John w. Draper. ZAP
plausc. lie had Investigated the sub
jcct. and his familiarity with physics
and optics gave him n clcw to impor-
tant improvements, which he soon an
nounccd.
Dagucrrc's process was. In brief. Ia
place u piece of copper plate with silver
over u vessel III iodine. when heated,
the vapor of iodine attacked the silver
and produced u coating of iodidc Of sill
yer; the plate was then placed In a cam
era. and when the image fell on the won.
sitive plate, u picture was produced.
This WIS not apparent at first. Da-
guerre could see no trace of a picture.
He slowed away the plates in a dark
closet; when he brought them out sew.
eral weeks a%ftcrward. behold, the pic.
lures had come forth clear and distinct.
In searching for the agent that devel-
opcd them, he discovered some mercu.
nv. and. on vnporizing this, found at
last the needed substance. A gentle.
man in Brooklyn has revived what may
be- called the ''lost art" Of Dayucrrc,
and o produces very perfect speci.
mems II these pictures.
Landscapes was all that Dagucrre
could take; ~ II required IN hour Ia
fix the picture, no human endurance
was equal to such n strain. DR.. Ora.
per found that by inverted lenses he
could shorten tho time. II was supposed
that the yellow tinge Of the complexion
would be fatal To the picture. Draper
used to bring out n dredging box from
tho kitchen, and powder the face Of the
sitter, who was then placed under blu,
glass. II he could hold ont for twenty
, minutes. he secured n picture. In fact,
Dr. Draper often took his own picture,
sitting down calmly in front of his cam
era for u half-hour, and then proceeding
to develop the negative. But the great
trouble with daguerrotypes was the OK.
pensc. E.ch picture required a new
plate.
An E~nglishman. Fox Talbot, pro
duced u silver paper photograph. which
WAS the germ Of the modern process,
Talbot's process is now carried on in
Germany. II was largely used during
the Franco-Prussia war for the makipo
y, pr maps. An hour after n survey had
bccn made. an officer could be provided
With u good map Of the hostile terrific,
". Several chemists tried To find some,
hing better than paper to hold the sen
litlSed silver salts. The great develop
s'Sus Sutiiu III ioti WneU CnOnDlp OI
sasle, discovered gun-cotton. Cotton,
~ found. when exposed to nitric acid
became explosive, and soluble In a mix,
ure OF alcohol and ether. The discov,
(ry OF this latter property WAS tn,
oundation OF photography. When u
otton Is dissolved in alcohol and ether,
ullodion results; II forms n film on tn,
Eirface Of y plate which holds the sill.
pr salts. 1t gives us all our negatives
ON which thousands Of pictures may
. struck oil.
The process Of taking a picture wa
Zen shown by the professor and his as.
stants. The camera obscure used was
large one, employed in \ recent for.
'ry suit to detcct the spurious sigma.
res to several checks. 1t was the re-.
'rse OF those in common use, the pic
70 being placed inside and the ground
ASA plate without. A cap, the iectur.
said, Is an important part of the
camera, but sometimes It plays sad hav.
%. One of the English parties who
/ want mt m TAXA rsa.. -