New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1899-03-19

from twenty thousand TO nifty thousand lines 10
the inch vere cut \ diamond point carefully
selected did the business
It should b. borne in mind that spectrum
obtained in this manner can be examined WIN
an eyepece that il focused 10 cover any part'r-
ular part Of it. The 0bscry can look al me
red Or The violet or Tho green alone. ana IL the
spectrum is sufficiently expanded or magnUlri
ne can scrutirize a limited portion Of any color.
4 wide spacing between lines gives di"efe"'
ulagnincatiou Of the spectrum than cl'9'
suacing Two spectra obtained by eratings oi
different spacing might boz put side by side an"
II would then Dee noticed that the red III one "u
not come directly opposite the red ot 'he o'"r''
but that in the mere matter OF position they
failed TO match. This being the case. II "ou'n
r-ollir- only q certain adjustment OF the aPP@
ratus I'd make the eyepiece cover the req oil one
sp,ctrum and the blue. on any olh'r Color Oh inv
other. This prnripl. would Apply Il d '"''U
grating were employed ana IL third spectrum"
produced.
The picture that Professor Wood produces
s,.rps to be composed of nothing bur hne parliie
lines IL some parts Of picture '"1S az
spac.d at on. rat.. at another ,hey have III
f.rent spacing and cI -where ,ney are spaced a
a third rate-in no instance more than TWO
I
sideration the means Boy which these lines nave
| - ,rs.,ih.d one can easily understand this
much. If the spacing has been rightly cIcu
/ lated and the focus OF a simple bit 81 vie"ihS
arnaratus has been properly adjusted the eye
/ viii simultaneously catch the green from one
/ SCI of lines The. blu. from another and tn fed
/ from a third.
II Boy some magic Professor Wood has ar
shaded the right ruling for green to occupy Only
| tbose parts OF his plate where he wants sI"'h'
tb.. right sracing Tor blue % occupy those places
where he wants blue and the right spacing lot
red 70 occupy those parts Of the plate where ne
wants red the thing is done This II eNacuy
what the Wisconsin man says he has done his
final picture is I'D black and white and III me
lines differently spaced in different portions Out
when examined with the proper apparatus VIII"
light that comes through it a. through Trans
rarency. thu correct colors and shadinSs are re-
vealcd to the observer
The mode Of producing the plate Is conipi-
Gated and not easily explained But the pa'uc-
,,l.rs will be laid before the public before long
Professor Wood hopes To simplify The process !"
time At present he uses the thre"-coi'r 5''r'"
plan. ard has three negatives o. start Win nc
| thinks that H. needs only 10 ma plates ''A'
can be made aensitive To all c"ors Of the spec
trum, ana that hav" j inner 5'l" man 49,
now in tn. market in orler To get along WIN
! one negative.
Until the public has chance to examine these
pictures and to judge for Itself it viii no, be
possible to form a definite idea Of the value d
the method But it has rational basis IL ought
to yield purer colors than the old three-soie'"
process and, although it requires spec'I' III
strument for looking at the pictures the ia''e''
once made can be reproduced without hmh