New-York tribune., 1904-10-16
STRANGE PHOTOGRAPHY.
Sensitive Plates Affected By Resin
Ous Woods.

T,y.4sbla radiatous that act upon the chemicals
os a Photographic plate come from other sources
than uranium radium thorum and allied metals
They also emanate from certain vegetable products
Or william 7 Russell an Engishnan. recently
described before the Royal Society IN London some
surprising results which he had observed Nearly
al woods appear 10 possess this strange property
though some are more powerful than others. An
exposure OF from half hour 70 eighteen hours
"a headed 70 proouce impression The wood
should be IN contact with the plate. or close 70 It
The wood OF conc bearing trees Is especially ac-
tive.
picture shown by Dr. Russell was derived from
a cross sectton OF a branch OF q Scotch fir. and
showed distinctly the rings formed there by tho
annual growth The radiation here seems TO come
from that portion which was added in the spring.
and the autumnal portion had apparently little or
no influence. The change has been attributed to
hydrogen peroxide smitte. By the rosins In the
wood, and these exist in both parts However. It
Is suggested that perhaps It is confined in ths
autumnaI haS OF the ring in such way that Il
cannot escape. Experiments with spruces show
that radiation occurs from all parts OF the section
alike. Hence rings are not well defined With the
larcn again. there is reversal OF the behaWor
OF the hr. There is enough difference between the
sprtng and autunnal growths 20 make an impress
sion Tor every year the latter Is the most
effective
allied bodies can. when used alone be proved TO
bs very active. some naturally much more so thala
ofhers Ordinary rosins. Burgundy pitch, gum
nagfc
but true gums. gOcn a gum senegal
~ md gum RraDac entirely without action on "A
pnotogra phic plate =, ,,,
,StSrnent that feeble Photographic action had been
eSserved il printers ink and that old books would
.o+netiTues exercise IL. Accurate copies OF print
eonid thus be obtained. although contact OF sew
orsI days was sometimes necessary Al that time
n vas suspected that Il was the resins IN the ink
,-bfch produced the effect.
rhe most novel of the revelations made by Or.
4,+1SseIl IN his recent lecture was that WOOD has
l-oDsrfv which has hitherto been observed only n
= SeT minerals. II exposed TO strong light It will
o. the and aft6rWaF0 give them
~ though the rays IN question csI1not De seen
sle Dsouarty is manifested IN the hoAoNlLs man
Ser: piece OF black paper or anfon Is isld on
~ az pine board, as TO cover only hetI OF the
t.er md the whole is then exposed 20 the light.
a nhotogra phic plate having been 9fterWafd ap"
--,i,Sd 70 the wood the portion Wnlch was u4uTni-
gtnlees acts more powerfully than the rest II Is
L-sSible OF course that instead OF true radiation
SeSng Involved. chemical change Is Sheotea In the
Tvood or some Ingredient thereof puI Ins phe-
nonenon Is not the less mysterious. ~. q hassen
cDss out that the increase IN actiVIty y not uni
pe Ia consequence OF the illumination, but that
ssbozs parts which are already active, and which
s.SrIif reveal the texture OF the Wooos act more
vongly Bodies like sugar, starch At.o hour which
beiays n thAs 1Anxsr