New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1869-12-11

should 10 carefully excluded from the ar until it is
CURED for in order 10 sS DgtSg 700 thick
cent of OIL after which the prepared OH may De added
. PERCEPTION or CoLOR.-EXperiments have
recently been made Germany to ascertain the relative
time required 10 discern different coors II was found
that the color easily and quickly distinguished ia
bTgbt Velnw while those most difficult 20 recognize are
the red and violet Bright olive comes next after yellow
i'm being readily perceived and green seems TO occupy
middle position These experiments may have some
weight With those who deysing signal lights to guide
why red and violet are not quickly perceived is that
they are the opposite extremes Oh the solar spectrum
and extend respectively 10 lhe I on p NOMINATIONS
10 give any impression OF hsh IN Ine other hand
the least sensitive shOnd be most Impressed as that
OF the young child is by the red because Is produced
by the longest fluctuations, which are also those Of least
velocity.
REFLECTED SUNLIGHT IN PHOTOGRAPHY
Dr. H. Vogel the German correspondent OF The Phadet
pLa photographer after abiding 10 new Photographic
light atey used i'm Vienna which consists OF oxide of
tftanium heated by hydrO.oXygen flame, says he has
lost much confidence in all artificial hghts HIS expert
ence in the Egyptian tOmbs the cause OF IT, In many
OF them he mad burned largo quantities OF magnesium
wire without arriving at any satisfactory result, 0nd
succeeded finally much better with reflected sunlight
An opening was made in a funeral vault the rays OF
sunlight were caught by mirror ana thrown on the
object The effect was better 90 feet Of magnesium
wire BY moving the mirror the light gdcs over the OBJ
ieCt, this way. he had copied pdlhtlng, dark
corners, ceilings, etc. His example has been initiated
Tie photographer HammcrsChmidt has recently
taken The interior OF the Church Of the Holy sepuchre,
at Jerusalem; also the AnUintmcnt stone OF Chst, IN
the same church, by means OF reflected Ight lie has
succeeded admirably where all former attempts have
proved failures In all these proceedings, uIeeuy 70
Elected light proved efficient Lately Dr. EOge tred to
make picture with dOublereilccted lghti the object
was gas machine which stood IN dark corner OF tho
Royal Academy; il could not be reached by direct re-
Elected hight He had to use two mirrors ana the rays,
after second reflection had TO be Kept longer on the
dark parts OF the object than the light ones Inc lens
was sIcinhei Aplanatic No. .. with the mira stop;
time. july -, between ana p m lie lounu tnat an
exposure from eight TO minutes was necessary 10
obtain good negative. This goes 10 show how large
9 acuic force lost 10y reflection; as the same
lens with direct light, would have required an exposure
of twenty-five seconds In tins connection he mentions
the extraordinary difference the aCtlnsm OF sunlight,
during different OF the year. For Instance under
the Goth parallel Of northern latitude the intensity Of
the DIST of December, at uOun Is On] equal 10
the intensity az % D. the 2lsi OF july In tins re-
spec the photographers OF the Southern hemisphere have
he advantage over us a. with them, Christmas happens
in Midsummer