The Portland daily press., 1899-12-07
RECEIVER

The priv cipls of the tslf ctro' cops deper DIS
upon the fact that any image produced
upen the re irs ef the eye Is only the
blenc Jog OF an iufini,e number Il rciuts
pro. Zee ell SCI arstely from the obj c., seen
by separate rays of IL ht. 1t IL not nsc-
essary that all these pc ints reach the eye
at exc city the same moment. The vi ion
" ill still be peri. CT though some come
FRI on of a ST cond later than others, or
though they all come at sc &C sssivs inter
walls, provided they be short enough. The
s'persistenc, of vision" of the eye will
bring them together in complete pic
ture, Just as 1t makes a circle Of lire out
OF a glowing match end when II IL moved
sw iftly round and round. Szszepanik
has found a way Of separating any image
that may be formed by an ord iusry photo
graphic lens into lite component luminous
points of transm iii ng these pei ats sepa-
ratsiy, but with enormous rapidity, over
" res and OF letting the eye Ieconstituts
them at the other end into the original
picture.
1t therefore seems the peril led teiec.
trofcope works something after this fash
ion. Two vibrating mirrcrs do the work
Of resolving the image intl points and
project them upon selenium disk,
Selenium Is a rare element, s,msthing
like sulphur. which has the singular
property of transforming waves OF light
lntO waves VI ClSNgtlCiSys ~ tuae ~ rays
Of light be thrown upon selenium disk
from which wires extend 1t will be found
on closing the c,tcait, that current Is
set up In the wires
Furthermore, and more important.
thess rays Of light. differing In color az d
intensity. prodrcs currents which differ
in intensity, escA particular ray having
its corresponding current, and no two
of them alike.
The mirrors are metal plates, fixed on
sounding boxes, and are kept IN c,ntin-
ued vibration so long as an eli cir!c bell
at csrtain pitch is sounded somewhere
In the apparatus. Furthermore as these
NJ etal plates and their sounding boxes arc
tuned to the pitch OF ths cit C .ric bsll, the
two mirrors must vibrats al uniform
rate, 900 or 4,000 times second. And
In the same way the two mirrors In the
recsiver must vibrats In unison with the
far away other pair.
How these mirrors vibrating. say.
1000 times a second-break up the imaRe
into tiny points of light and transmit
them at the rate of 4,o0) to the seclud
Is marvellous story. Though mirrors,
they are bls ckened, SO that they rst1s CT
only one line each, as fine as the edge of
knife blade. In the first bisckened
plate the mirror line runs crosswise; in
| the second it runs lsngthwise, 50 that
while the frat, vibrating, rshects sue ses-s
sive lines on the second, the latter reflect
only single points OF these lines upon the
selsnium cell.
Transforming the waves OF light into
waves of electricity, the selenium oi7k
gives them to the wires Tor transmits J.
At the other end the series OF electric
Impulses. sciing on two steel plates. or
clips" cause them to open and close, 90
| that the band of light tstwesn them con-
stantiy changes in intensity. Ths two
mirrors in the receiver, being arranged
like the two In the trsnsm liter. with thu
same periods OF vibration, and the Same
narrow lines of reflection, pick out single