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8/16/2019 US patent 241909 to A.G. Bell and S. Tainter, entitled “Photophonic Receiver”, issued 1881.
1/7
2 Sheets-Sheet 1 .No Model.)
‘
A. G . BELL
L
S.
TAINTBR.
P h o t o p h o n i o
R e c e i v e r .
No. 241,909. Patented May 2 4 , | 8 8 1 .
1
l l
n. »nenawww,uninpm . c .
8/16/2019 US patent 241909 to A.G. Bell and S. Tainter, entitled “Photophonic Receiver”, issued 1881.
2/7
( N o
M o d e l . )
2 Sheets-Sheet
2 :
y A .
G .
BELL
» S .
T A I N ‘ I ‘ E R .
Photophoníe
Receiver.
No.
241.909. ‘
Patented
May 24, |881.
WaZîwäw ~
Inner/wr@
¿ähm/smv
mim/4,3
n .
Pneus. meumqnpm wmv-M
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8/16/2019 US patent 241909 to A.G. Bell and S. Tainter, entitled “Photophonic Receiver”, issued 1881.
3/7
30
3 5
UNITED S T A T E S
PATENT O E E I C E , ì
ALEXANDER G . BELL
AND
’SUMNEE TATNTEE, or WASHINGTON,
D .
c.\
PHOTOPHONIC
RECEIVER.
SPECIFICATION forming p a r t o f L e t t e r s Patent No.
2 4 1 , 9 0 9 ,
d a t e d May 4 , 1 8 8 1 .
Application
f i l e d
March
4,
1 8 8 1 .
(No
m o d e l . )
i
. T o a l l whom i t may oncern:
Be
t known
t h a t
w e , ALEXANDER
GRAHAM
BELL and SUMNEE TAINTER, b o t h o f Wash
i n g t o n ,
i n
t h e D i s t r i c t o f
C o l u m b i a , have n
vented
a
new
a n d
u s e f u l
Improvement
n
P h o
t o p h o n i c
R e c e i v e r s f o r t h e Production
and
R e p r o d u c t i o n o f Sound by t h e A c t i o n o f
Radi
a n t
E n e r g y ,
which
i n v e n t i o n
i s
f u l l y
s e t f o r t h
i n
t h e
f o l l o w i n g s p e c i f i c a t i o n .
The i n v e n t i o n r e l a t e s more
p a r t i c u l a r l y
t o
t h e
r e p r o d u c t i o n
o f
a r t i c u l a t e s p e e c h p h o t o
p h o n i c a l l y - t h a t i s , by t h e a c t i o n o f r a d i a n t e n
ergy f rom
the
sun or other suitable source-but
i s a l s o a p p l i c a b l e , i n whole
o r
i n p a r t , t o t h e
p r o d u c t i o n o r r e p r o d u c t i o n o f o t h e r
s o u n d s , t o
t h e
p r o d u c t i o n o f
e l e c t r i c a l
and o t h e r
e i î ' e c t s ,
and
t o
o t h e r p u r p o s e s . I t i s
intended a s a n
improvement u pon t h e
photophone
f o r
which
L e t t e r s P a t e n t N o .
2 3 5 , 1 9 9
w e r e g r a n t e d
t o
Alexander
Graham
B e l l December , 1 8 8 0 .
The s a i d
p h o t o p h o n e
c o n s i s t s , g e n e r a l l y , o t '
a photophon ic
t r a n s m i t t e r , b y which
a
v i b r a
t o r y o r u n d u l a t o r y
beam
o r
p e n c i l
o f
r a y s
i s
produced,corresponding i n
i t s v i b r a t i o n s
o r
u n d u l a t i o n s w i t h t h e
a t m o s p h e r i c
v i b r a t i o n s
t h a t r e p r e s e n t
t h e sound t o be
produced o r
r e p r o d u c e d ,
and
a
p h o t o p h o n i c r e c e i v e r ,
by
which
the
v i b r a t i o n s o r
undulations
n t h e s a i d
b e a m r p e n c i l o f r a y s a r e converted
i n t o
sound
waves,
or i n t o vibrations i n a n e l e c t r i c
current
that can
be
converted i n t o sound-waves.
The p r e s e n t
i n v e n t i o n
has
r e f e r e n c e
t o
t h e
p h o t o p h o n i c
r e c e i v e r , a n d c o m p r i s e s
means
o r
converting
the “ radiant
v i b r a t i o n s , ”
a s
the
i
b r a t i o n s o r
undulations
o f t h e b e a m
o f
rays
may
b e c a l l e d , i n t o
s o u n d - w a v e s ,
a n d
a l s o i n t o
e l e c t r i c
` v i b r a t i o n
.
As e s c r i b e d
i n
t h e a f o r e s a i d p at e n t , t h e r a
- diant vibrations were converted
into s o u n d
40
4 5
5 0
waves
by means o f t h i n diaphragms o f hard
r u b b e r ,
m i c a ,
a n d v a r i o u s o t h e r m a t e r i a l s , u p o n
which the radiant v i b r a t i o n s were
allowed t o
f a l l . The sound was conveyed t o t h e
e a r
by a
h e a r i n g - t u b e connected w i t h a
sound-chamber
i n
t h e
r e a r
o r unexposed s i d e
o f
t h e
diaphragm,
which t s e l f formed o n e s i d e
o f
s a i d chamber,
o r a part o f one
s i d e .
With t h i s
apparatus,
a l t h o u g h
i t
i s
n o t v e r y
s e n s i t i v e ,
m u s i c a l n o t e s
w e r e p r o d u c e d by r a p i d l y i n t e r r u p t i n g
a
beam
which wasallowed o f a l l upon t h e diaphragm.
The m u s i c a l n o t e s
c o r r e s p o n d e d i n p i t c h t o
t h e
r a t e
o f i n t e r r u p t i o n ,
and were
l o u d
enough
t o
b e easily
heard.
_
We
ave
d i s c o v e r e d t h a t t h e l o u d n e s s o f t h e
sound i s
i n c r e a s e d
by
h a v i n g t h e i l l u m i n a t e d
5 5
o r
exposed
s i d e
ofthe
s e n s i t i v e
me di u m
i n
con
t a c t
with t h e a i r o f the s o u n d - c h a n . ber with
which
t h e e a r - t u b e i s c o n n e c t e d , and y a l l o w
i n g
t h e r a d i a n t
beam
t o
f a l l upon s a i d medium
through a p l a t e o f
g l a s s
o r
s i m i l a r m a t e r i a l 6 o
which i s t r a n s p a r e n t t o r a d i a n t e n e r g y ,
but
opaque o r
l e s s transparent
t o sound-waves.
I n t h i s way t h e f u l l
e i f e c t
o f
t h e
r a d i a n t v i b r a
t i o n s
upon
t h e s e n s i t i v e me di u m
i s
o b t a i n e d ,
and
t h e r e s u l t i n g sound-waves a r e
s h u t
i n
and
6 5
conveyed
t o
t h e e a r
w i t h approximately
t h e i r
f u l l f o r c e .
We
ave f u r t h e r
discovered that a
dark
or
black
c o l o r
i n t h e
s e n s i t i v e
me di u m s a dv a n
t a g e o u s , and t h a t w i t h
s u b s t a n c e s
i n
a n
o p e n , 7 o
p o r o u s , o r subdivided
c o n d i t i o n
l o u d e r sounds
a r e i n
g e n e r a l
o b t a i n e d
t h a n w i t h diaphragms.
The b e s t e f f e c t s
a r e
obta ined with
lamp-black
d e p o s i t e d upon a s u r f a c e o f
g l a s s
o r
o t h e r
hard
o r r i g i d m a t e r i a l . With a
l a y e r o f
t h i s
s u b -
7 5
`stance
as the
sensitive
medium,
articulate
Y
s p e e c h
h a s b e e n
r e p r o d u c e d
by t h e d i r e c t a c
t i o n o f r a d i a n t energy
upon
s a i d medium. In
t h e experiments i n which t h i s r e s u l t was ob
tained
s un b e a ms
were r e f l e c t e d from a mirror 8o
o f t h i n g l a s s s i l v e r e d , ( a s d e s c r i b e d i n
L e t t e r s
P a t e n t
N o .
2 3 5 , 4 9 6 ,
g r a n t e d
t o u s
December
4 ,
1 8 8 0 , )
a n d t h e
m i r r o r , b e i n g t h r o w n i n t o
v i b r a
t i o n
by
h e v o i c e , causedmore o r l e s s
o f t h e s u n
beams
t o
f a l l
upon
t h e
lam
- b l a c k .
The
a t t e r
8 5
was d e p o s i t e d upon t h e i n n e r w a l l s o f a sound
chamber a v i n gone
sideformed
f
a g l a s s p l a t e
t o t r a n s m i t t h e
r a d i a n t
beam, and having
an
e a r - t u b e communicating w i t h
t h e
i n t e r i o r , a s
e x p l a i n e d a b o v e . 9 o
A r t i c u l a t e s p e e c h h a s a l s o b e e n r e p r o d u c e d
with
areceiver containing a m a s s f lamp-black
Y
i n a
l o o s e
p u l v e r u l e n t
c o n d i t i o n .
A ump o f
l a m p - b l a c k , when e x p o s e d i n t h e
s o u n d - c h a m
b e r t o t h e
a c t i o n
o f an i n t e r m i t t e n t beam, g i v e s
9
a
l o u d
s o u n d , b u t i n f e r i o r t o t h a t g i v e n by
t h e
same substance i n t h e form o f l o o s e powder r
a
d e p o s i t e d
l a y e r .
I n s t e a d
o f
smoking
t h e w a l l s o f
t h e
sound
chamber,
a
p l a t e o f g l a s s , m i c a , o r
o t h e r m a t e -
r o o
r i a l
can
be
smoked and
p l a c e d
i n
s a i d chamber
s o t h a t t h e l i g h t f a l l s upon t h e smoked
s u r f a c e .
8/16/2019 US patent 241909 to A.G. Bell and S. Tainter, entitled “Photophonic Receiver”, issued 1881.
4/7
IO
2 5
30
3 5
4 5
S O
5 5
2
2 4 1 . 9 0 9
The o u d e s t
sounds
w i t h t h e i n t e r m i t t e n t
beam
have been obtained
by
means o f an
open
Wire
gauze
smoked
o r
covered with
a d e p o s i t of
l a m p - b l a c k .
With a
t u b u l a r r e s o n a t o r
having
t h e i n t e r i o r smoked a l o u d sound s produced
when
an
i n t e r m i t t e n t
b e a m
having
t h e proper
r a t e
o f v i b r a t i o n i s
allowed t o
f a l l i n t o i t .
Numerous
x p e r i m e n t s
have b e e n made
w i t h
v a r i o u s o t h e r
s u b s t a n c e s . Black
worsted
may
b e mentioned a s g i v i n g , w i t h t h e i n t e r m i t t e n t
b e a m ,
a
g o o d
s o u n d , a l t h o u g h
much i n f e r i o r
t o
l amp b l a c k .
Fibrons material
coated with
l a m p - b l a c k has a l s o been u s e d .
C o n d u c t i n g - b o d i e s
g e n e r a l l y , i n a p h y s i c a l
c o n d i t i o n s i m i l a r t o l a m p - b l a c k , e s p e c i a l l y i t '
o t '
dark
o r b l a c k c o l o r , _ y i e l d good s o u n d .
Spongy
p l a t i n u m s h o u l d b e
p a r t i c u l a r l y
men
t i o n e d . O t h e r
m e t a l s
o r m e t a l l i c c o m p o u n d s
a s s i l v e r ,
c o p p e r ,
b l a c k
o x i d e
o f manganese,
a n d
t h e
like-are
a l s o s e n s i t i v e t o
r a d i a n t
en
e r g y , and
g i v e o u t sound by t h e d i r e c t
a c t i o n
o f a
v i b r a t o r y
b e a m . The p r o d u c t i o n
o f sound
i n t h i s way
i s
conceived t o be
due
t o
au ab
s o r p t i o n and e x p u l s i o n o f
t h e a i r b y t h e v i b r a
t o r y medium
a c t i n g ,
a s i t w e r e ,
l i k e a
sponge.
Thus when t h e energy o f t h e
r a d i a n t
beam i n
c r e a s e s t h e
p a r t i c l e s
composing t h e
v i b r a t o r y
medium
expand
and x p e l t h e a i r l ' r o n i
between
t h e m , and
when t
d e c r e a s e s t h e r e v e r s e a c t i o n
t a k e s
p l a c e
and
t h e
a i r i s a g a i n
a b s o r b e d .
T h e s e r e p e a t e d
e x p u l s i o n s and a b s o r p t i o n s
a r e
p r o p o r t i o n a t e t o
t h e
r i s e
and f a l l o f radiant
1 1
e r g y , and
p r o d u c e c o r r e s p o n d i n g c o n d e n s a
t i o n s and r a r e t ' a c t i o n s - o r , i n
o t h e r w o r d s ,
s o u n
d - w a v e s - - i n
t h e
s u r r o u n d i n g
a t m o s p h e r e .
Heat
due
t o t h e a b s o r p t i o n o f
t h e
r a d i a n t en
ergy seems
t h e r e f o r e
t o b e
t h e
p r i n c i p a l agent
i n
p r o d u c i n g t h e s o u n d - w a v e s .
In t h e
photophone
a s
d e s c r i b e d
i n Patent
N o .
2 3 5 , 1 9 9 ,
a b o v e m e n t i o n e d , t h e r a d i a n t v i
brations were converted i n t o e l e c t r i c a l vibra
t i o n s by a
d i t T e r e n t
m a t e r i a l from any used f o r
t h e d i r e c t
p r o d u c t i o n
o f sound - w a v e s , t h e
p e c u l i a r
s u b s t a n c e s e l e n i u m b e i n g
e m p l o y e d .
The
r e s i s t a n c e
w h i c h s e l e n i u m - ‘ w h e n p r o p e r l y
p r e p a r e d ,
o f f e r s t o
an
e l e c t r i c
c u r r e n t was
*knownr
t o vary
under
t h e inñuence o f rays from
the
sun
or other suitable source of radiant
en
ergy,
a n d
t
was
therefore
employed
as the
me
dium f o r c o n v e r t i n g t h e r a d i a n t i n t o e l e c t r i c
v i b r a t i o n s . I t
was included i n the c i r c u i t o t ' a
g a l v a n i c ba t t e r y a n d p l a c e d
i n s u c h
p o s i t i o n
t h a t t h e r a d i a n t
b e a m
f e l l upon i t . The va
r i a t i o n s i n
t h e r a d i a n t
energy
due t o t h e v i b r a
t i o n s i n
t h e
beam produced
c o r r e s p o n d i n
g va
r i a t i o n s i n
t h e
r e s i s t a n c e o f the selenium
and
i n
t h e g a l v a n i c
c i r c u i t
o f
which
i t formed a
p a r t , and
c o n s e q u e n t l y
i n
t h e
t e n s i o n
o f
t h e
c u r r e n t
o n
s a i d
c i r c u i t ,
o r , i n
o t h e r w o r d s , t h e y
produced e l e c t r i c a l v i b r a t i o n s i n t h a t
c i r c u i t .
By
h e
a i d o f c e l l s c o n s t r u c t e d t o expose a
l a r g e
s u r f a c e o t ` t h e
s e l e n i u m ,
and t h e p r o p e r
p r e p a r a t i o n o f t h e l a t t e r , an a p p a r a t u s was
produced
s o
s e n s i t i v e t o
v a r i a t i o n s
i n
r a d i a n t
e n e r g y t h a t ,
w i t h
a
s u i t a b l e
p h o t o p h o n i c
t r a n s
m i t t e r and w i t h a n
o r d i n a r y
h a n d - t e l e p h o n e
and g a l v a n i c c i r c u i t c o n n e c t e d w i t h t h e
p h o t o
p h o n i c r e c e l v i n g
a p p a r a t u s ,
a r t i c u l a t e
s p e e c h
was r e p r o d u c e d p h o t o p h o n i c a l l y .
We
ave
discovered t h a t the same
me d i u m
used t o
produce
m u s i c a l
n o t e s
o r t o reproduce
s p e e c h
by
t h e
d i r e c t
a c t i o n o f
t h e r a d i a n t
v i
b r a t i o n s
can
be used t o convert the l a t t e r i n t o
e l e c t r i c
v i b r a t i o n s .
I t '
a
l a y e r
o f
lamp-black
i s included i n
an
e l e c t r i c
c i r c u i t and
i s exposed t o
t h e a c t i o n
o f
a vibratory
beam t ' rays from
the
sun o r
other
s o u r c e , v a r i a t i o n s a r e produced i n
t h e
e l e c t r i c
r e s i s t a n c e o t ' t h e l a m p - b l a c k , which v a r i a t i o n s
c o r r e s p o n d t o t h o s e i n
t h e
energy
l '
t h e
v i b r a
t o r y b e a m . I t ' a n i n t e r m i t t e n t b e a i n
i s
a l l o w e d
t o
t ' a l l
upon
t h e l a m p - b l a e k ,
e l e c t r i c a l i m p u l s e s
a r e produced
i n t h e
c i r c u i t i n
which thelamp
b l a c k
i s
i n c l u d e d
c o r r e s p o n d i n g t o t h e
r a d i a n t
i m p u l s e s o f t h e beam, and t ' a t e l e p h o n i e r e
c e i v e r
i s
a l s o
included
i n
t h e
c i r c u i t
a
m u s i c a l
note
w i l l
he h e a r d . I l ’ an
undnlatoryor v i b r a
t o r y beam
f r o m
t h e
r e t l e c t i n g - t r a n s i n i t t e r b e
f o r e
m e n t i o n e d , o r o t h e r s p e a k i i i g - t r a n s m i t t e r
which
g i v e s
t o t h e beam
v i b r a t i o n s s i m i l a r
i n r a t e ,
a m p l i t u d e , and q u a l i t y
t o
t h e
s o u n d
waves
o t ' a r t i c u l a t e s p e e c h , i s allowed t o t ' a l l
upon t h e l a m p - b l a c k , t h e e l e c t r i c und l a t i o n s
o r v i b r a t i o n s
i n t h e
galvanic
c i r c u i t
w i l l r e p v
r e s e n t
t h e words and s e n t e n c e s which produ ced
t h e
v i b r a t o r y b e a m ,
and i t t h e
a p p a r a t u s
i s
s u i i i c i e n t l y
s e n s i t i v e t h e s e
words and s e n t e n c e s
c a n b e r e p r o d u c e d
by
a n o r d i n a r y
t e l e p h o n i e
r e c e i v e r . The use o t '
selenium,
which
i s o b
j e c t i o n a b l e f o r r e a s o n s based
upon t h e nature
ofthe
substance
t s e l f ,
a s
w e l l
a s
upon t s
high
p r i c e and
s c a r c i t y , c a n
t h e r e f o r e b e d i s p e n s e d
w i t h . The
same
o b j e c t i o n s do n o t apply t o
l a m p - b l a c k .
The
a c t i o n o f r a d i a n t energy upon t h e v i
b r a t o r y medium
t o
p r o d u c e v a r i a t i o n s
i n
t h e
e l e c t r i c a l
r e s i s t a n c e o t ' the
l a t t e r appears t o
b e
s i m i l a r t o
t h a t i n
p r o d u c i n g sound
by d i
r e c t
action-that
i s t o s a y , t h e p a r t i c l e s
a r e
b r o u g h t t o g e t h e r o r
moved a p a r t a c c o r d i n g
t o
the i n c r e a s e o r decrease
o t '
the
energy
o t '
t h c beam.
They
c o n s e q u e n t l y f u r n i s h t o t h e
e l e c t r i c current
a path
of l e s s
o r greater r e `
s i s t a n c e .
All conductors
i n
a
p h y s i c a l c o n d i t i o n
s i m i
l a r t o l a m p - b l a c k
have
t h e i r e l e c t r i c a l r e s i s t
a n c e a f f e c t e d b y
r a d i a n t
e n e r g y . Spongy
p l a
tinum
i s an example.
We ave d e v i s e d
a
form o f
c e l l
whereby any
d e s i r e d e x t e n t o f
s u r f a c e o f t h e lam
b l a c k
can
b e exposed
t o
t h e r a d i a n t energy without
i n
t r o d u c i n g undue
r e s i s t a n c e
i n t o
t h e e l e c t r i c
c i r c u i t .
R e f e r e n c e
has h e r e i n b e f o r e been
ma de
t o
t h e
c e l l s used
with
s e l e n i u m .
These
e l l s , t h e
con
s t r u c t i o n
o f which s f u l l y
d e s c r i b e d
i n L e t t e r s
P a t e n t N o s . 2 3 5 , 4 9 7
and 2 3 5 , 5 8 8 ,
b o t h d a t e d
December
4 , 1 8 8 0 , c o n s i s t , m a i n l y , o f t w o o r
more o n d n c t i n g
s t r i p s , p l a t e s ,
o r d i s k s , p l a c e d
s i d e
by
s i d e
and
s e p a r a t e d
by
t h i n s h e e t s o f
i n s u l a t i n g m a t e r i a l , w h i c h e x t e n d
n e a r l y
t o t h e
e d g e s
o f t h e
p l a t e s , s o
a s t o
l e a v e
a
narrow
7 0
7 5
3 5
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9 5
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1 0 5
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and
s h a l l o w b u t l o n g s p a c e t o
r e c e i v e t h e s e
l e n i u m . The p o l e s
o f t h e b a t t e r y
b e i n g ' c o n
n e c t e d w i t h t h e
p l a t e s
which f o r m r t h e c o n d u c t
o r s
o f t h e
c e l l ,
t h e c u r r e n t f l o w s
from one t o
t h e o t h e r
t h r o u g h
t h e
s e l e n i u m , m e e t i n g b u t
s m a l l
r e s i s t a n c e
on account
ofthe
t h i n n e s s
o t '
t h e selenium l a y e r . In some
c a s e s t h e s e l e
nium
was c a s t around m e t a l l i c p i n s embedded
i n
i n s u l a t i n g m a t e r i a l
c o n n e c t e d
w i t h t h e p o l e s
o f
t h e b a t t e r y .
In
t h e
p r e s e n t i n v e n t i o n
t h e
conductors
a r e
f o r m e d o f
t h i n
s t r i p s ,
p l a t e s , s h e e t s , W i r e s ,
o r
f i l m s
?xed r
mounted
upon
an
i n s u l a t i n g back
i n g o r
s u p p o r t wi t h
t h e i r
e d g e s o p p o s e d and
near together,
so
as
t o
leave
o n e or more a r
row
channels
t o
r e c e i v e
t h e
s e n s i t i v e medium.
C e l l s
o f
t h i s
c h a r a c t e r a r e l n n c h
s i m p l e r than
t h o s e a l r e a d y p a t e n t e d , a n d
t h e y
a r e ,
b e s i d e s ,
b e t t e r
adapted t o u s e i n c o n n e c t i o n w i t h
lamp
b l a c k . The improved c e l l s
can
be
ma de
w i t h
a curved o r c y l i n d r i c a l s u r f a c e , although a
dat
s u r f a c e would
g e n e r a l l y b e p r e f e r r e d , and
t h e
c o n d u c t o r s `
can
be
m a d e
o f v a r i o u s
forms
and
metals.
Excellent
r e s u l t s
have
been
obtained
with a
c e l l h a v i n g `
two c o n d u c t o r s which
resemble i n
a p p e a r a n c e
combs w i t h w i d e - s p a c e d
t e e t h ,
and
which a r e
s e c u r e d t o
t h e i n s u l a t i n g -
backing
i n
such
r e l a - t i v e p o s i t i o n
t h a t
t h e t e e t h o f
one
c o m b
a l t e r n a t e o r
intermesh
with
t h e
t e e t h o f
the
o t h e r , but a r e not i n c o n t a c t with them.
The s e n s i t i v e medium
f i l l s t h e
s p a c e s between
t h e
t e e t h o f t h e
two c o n d u c t o r s ,
and by
i n
c r e a s i n g t h e number and l e n g t h o f t h e t e e t h
the surface can
be increased t o
anydesired
ex
t e n t . The
r e s i s t a n c e t o t h e
e l e c t r i c
c u r r e n t
w i l l ,
o f c o u r s e ,
depend
upon
t h e
mass
o r
a r e a
o f
s e n s i t i v e medium, and upon t h e d i s t a n c e
which s e p a r a t e s t h e t e e t h o f one c o m b
from
those o t ' the other. ‘
In order t h a t
t h e
e l e c t r i c current may
i o w
e q u a l l y
f r o m t h e
s e v e r a l
t e e t h , o r
g e n e r a l l y
from
one
conductor
t o a n o t h e r , i t i s
n e c e s s a r y
t h a t
t h e s p a c e s b e t w e e n t h e i r a d j a c e n t e d g e s
should be everywhere t h e s a m e .
We ave
found
t h a t a t i l m
o f s i l v e r depos
i t e d
upon
a g l a s s p l a t e by t h e methods o r d i
n a r i l y e m p l o y e d
f o r s i l v e r i i i g m i r r o r s i s
p o s
s e s s e d o f
g r e a t t o u g h n e s s ,
and c a n , w i t h a
s u i t a b l e
t o o l , b e r u l e d
o r
s c r a p e d o f f
i n s t r i p e s ,
s o a s t o
l e a v e
sharp edges l w h i c h appear
c l e a n
a n d
w e l l d e l i n e d ,
even under
a m i c r o s c o p e .
A s
t h e s i l v e r e d f i l m i s n o t a f f e c t e d i n j n r i o u s l y
b y
l a m p - b l a c k , i t i s , f r o m
i t s
g r e a t c o n d u c t i v i t y
a n d
t h e accuracy
with which
i t can be r u l e d ,
eminently adapted
t o
u s e i n t h i s
i n v e n t i o n
a s
t h e c o n d u c t o r o f t h e
p h o t o p h o n i c r e c e i v e r .
r l ‘ h e s i l v e r e d f i l m can be deposited upon a
curved
o r f l a t s u r f a c e ,
and
can
be
scraped o f t ’
i n s t r a i g h t , z i g z a g ,
c i r c u l a r , s p i r a l ,
o ‘ r
o t h e r
s u i t a b l e
l i n e s . The
width o f
t h e
s t r i p e o r
s t r i p e s r e m o v e d
i s
r e g u l a t e d b y t h e s c r a p i n g
t o o l , a n d
t h e p o s i t i o n
o f t h e l a t t e r i n
o p e r a t i o n i s
c o n t r o l l e d a n d a d j u s t e d by m e c h a n i c a l m e a n s ,
s o t h a t
t h e utmost e x a c t n e s s c a n
be o b t a i n e d .
I n
t h e
c e l l
b e f o r e
r e f e r r e d to
a s
givingex~
c e l l e n t r e s u l t s
t h e intermeshing combs
were
formed
b y s c r a p i n g
a s i l v e r e d
f i l m
from
a i l a t
g l a s s p l a t e ,
a s j u s t d e s c r i b e d .
T h i s f o r m
o f
c o n d u c t o r i s , h o w e v e r , o b v i o u s l y o f g e n e r a l
a p p l i c a t i o n , a n d c a n
b e
e m p l o y e d
w i t h
v a r i o u s
m e t a l s . For
example,
t h e combs
can be
c u t
f r o m
t i n - f o i l
a n d p a s t e d
u p o n
g l a s s . Thelamp
b l a c k i s a p p l i e d t o
t h e s e
c e l l s
by
smoking t h e
proper
surface
over a flame
f r o m
a
c o a l - o i l
lamp
o r
o t h e r s u i t a b l e b u r n e r .
The
lamp
b l a c k w i l l
b e d e p o s i t e d on t h e c o n d u c t o r s a s
w e l l a s
between them; but
t h i s
does
n o t i n t e r
f e r e
w i t h t h e
p r a c t i c a l workings
o f t h e appa
r a t u s .
The
d e p t h
o f t h e l a y e r
d e p o s i t e d
may
b e j u s t s u t t i c i e n t
t o
render t h e s u r f a c e s e n s i
b l y o p a q u e . The
c h a r a c t e r
o f t h e
r e s u l t
i s a f
f e c t e d b y t h e
d e p t h
and a l s o by t h c e x t e n t o f
s u r f a c e exposed
t o
t h e
r a d i a n t e n e r g y .
Al
though
no
s p e c i a l
e x t e n t i s r e q u i s i t e , a
very
l a r g e s u r f a c e i s n o t d e s i r a b l e , and t h e r e i s a
c e r t a i n
l i m i t -
a t which the best
r e s u l t s
a r e o b
t a i n e d i n any c a s e ;
but
t h i s
l i m i t v a r i e s
with
t h e
e n e r g y
o f t h e
r a d i a n t
beam,
t h e s t r e n g t h
o f
t h e
b a t t e r y ,
and o t h e r
c o n d i t i o n s , s o
t h a t
n o
s i m p l e r u l e c a n b e g i v e n . By d e p o s i t i n g
upon
the
s i l v e r e d
g l a s s ,
r u l e d o r
scraped
a s
e x p l a i n e d , a l a y e r
w h i c h
i s
s e n s i b l y o p a q u e
and w i p i n g i t o t ' f
g r a d u a l l y
a r o u n d t h e e d g e s ,
a
spot
o f s u i t a b l e s i z e a n d character can
be
readily
obtained .
The c e l l i s o r d i n a r i l y r s e c t i r e d
i n
p o s i t i o n i n a
sound-chamber
having
a
g l a s s
p l a t e f o r
t h e
e n «
t r a n c e o f t h e r a d i a n t beams,
and
t
i s s o p l a c e d
t h a t s a i d beams
f a l l
upon t h e l a m p - b l a c k .
I f
i t i s
desired
t o r e c e i v e
a message
r s i g n a l d i
r e c t l y ,
a s w e l l a s through t h e
i n t e r m e d i a r y
o f
t h e e l e c t r i c
c u r r e n t ,
t h e s o u n d c h a m b e r
i s p r o
vided with
o n e or more ear~tubes.
The lamp-black
c e l l
can be
l o c a t e d i n
t h e
main c i r c u i t
i n
which
the e l e c t r i c a l o r
t e l e
phonie r e c e i v i n g
apparatus i s p l a c e d ,
o r i t
can
beconnected w i t h a r e c e i v i n g - c i r c u i t
by
means
o f an i n d u c t i o n c o i l o r c o i l s , a s t e l e p h o n i e t r a n s
m i t t e r s u s i n g
a
b a t t e r y
have
been c o n n e c t e d .
H a v i n g e x p l a i n e d
t h e
g e n e r a l p r i n c i p l e s
o f
our
i n v e n t i o n ,
we w i l l now
roceed
t o describe
a p p a r a t u s c o n s t r u c t e d i n a c c o r d a n c e w i t h t h e
s a m e , » r e f e r e n c e b e i n g
had
t o t h e
accompany
i n g
d r a w i n g s ;
w h i c h f o r i n a p a r t o f t h i s
s p e c i
iìcation. -
F i g u r e
l i s
a
s e c t i o n a l
v i e w , i l l u s t r a t i n g
ap
p a r a t u s
f o r
t r a n s m i t t i n g
s p e e c h
p h o t o p h o n i
c a l l y
w i t h o u t t h e
a i d o f
a n
e l e c t r i c
e i i c u i t
F i g .
2 ,
a
s e c t i o n a l view
o f a
s l i g h t l y a l t e r e d form
o f
a
r e c e i v e r ,
shown i n connection
with
the
appa
r a t u s f o r
p r o d u c i n g a n
i n t e r m i t t e n t beam;
F i g .
2 “ ,
a
f r o n t
view
o f
one ofthe d i s k s
o f
t h e
i n t e r m i t t e n t - b e a m a p p a r a t u s ; F i e ' . 2 b , a s i m i
l a r view o f a wire-gau ze disk used i n the
r e
c e i v e r ; F i g s . 3 a n d 4 , v i e w s , i n s e c t i o n a n d
p l a n ,
o f t h e l a m p - b l a c k c e l l
w i t h i n t e r n i e s h i n g
combs
o f s i l v e r i i l m
F i g s .
5 and
,
p l a n v i e w s o f o t h
e r f o r m s o f t h e
c e l l ;
F i g . 7 ,
a
v i e w showing
t h e
c e l l i n c i r c u i t w i t h g a l v a n i c b a t t e r y
and
hand
t e l e p h o n e
and
t h e i n t e r m i t t e n t - b e a m a p p a - - y
r a t u s
a s ‘ t h e
p h o t o p h o n i c
t r a n s m i t t e r ;
. a n d F i g .
7 6 .
7 5
8 5
9 0
9 5
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2 4 1 , 9 0 9
8 ,
a v i e w , p a r t l y i n
s e c t i o n , i l l u s t r a t i n g
t h e
a p
p a r a t u s f o r t r a n s m i t t i n g s p e e c h , a n d s h o w i n g
a photophonic r e c e i v e r connected with a t e l e
p h o n i e c i r c u i t ,
and a l s o
p r o v i d e d
w i t h
means
f o r
c o l l e c t i n g a n d conveying t o
the
e a r o f
the
l i s t e n e r s o u n d - w a v e s
d i r e c t l y
p r o d u c e d .
The same
l e t t e r s o f r e f e r e n c e i n d i c a t e
l i k e
p a r t s i n t h e s e v e r a l
t i g u r e s
i n which t h e y o c
c u r .
Ais a r e f l e c t i n g p h o t o p h o n i c t r a n s m i t t e r ;
B ,
t h e i n t e r m i t t e n t - b e a m a p p a r a t u s ; C t h e
pho
t o p h o n i c
r e c e i v e r ; D ,
a g a l v a n i c c i r c u i t ; E , a n
o r d i n a r y h a n d - t e l e p h o n e ;
F , a n i n d u c t i o n - c o i l .
The
r e t i e c t i n g - t r a n s m i t t e r A o n s i s t s
o f a
m i r r o r
o f t h i n s i l v e r e d g l a s s , a , which s thrown
i n t o v i b r a t i o n s
by
t h e v o i c e o f
a p e r s o n
speak
ing
i n t o t h e tube a ' , a n d r e t l e c t s more
or l e s s
o f t h e
beam
o f
s u n l i g h t
o r o t h e r r a d i a n t beam
toward t h e r e c e i v e r
C .
The
i n t e r m i t t e n t -
be am
apparatus B c o m
p r i s e s
two d i s k - w h e e l s , b , w i t h a
s e r i e s
o f r a
d i a l o p e n i n g s i n t h e p a t h o f t h e
beam.
One o f
t h e s e
d i s k - w h e e l s
i s
s t a t i o n a r y
and
t h e o t h e r
r e v o l v e s ,
o r t h e y b o t h
r e v o l v e
i n o p p o s i t e d i
r e c t i o n s , o r i n t h e same
d i r e c t i o n
a t
unequal
v e l o c i t i e s . The
b e a m , b e i n g c o n s e q u e n t l y
c u t
o t t by t h e blank s p a c e s and a l l o w e d t o
p a s s
t h r o u g h
t h e o p e n i n g s when t h o s e i n
one
d i s k
r e g i s t e r
w i t h t h o s e
i n
t h e
o t h e r , i s i n t e r m i t t e n t
i n i t s a c t i o n .
A
eam
from
the s t i l l o r from
a n
a r t i f i c i a l
source can be
employed
with t h i s
a p p a r a t u s .
The beam can
be
c o n c e n t r a t e d
be
f o r e
o r a f t e r p a s s i n g t h r o u g h t h e d i s k - w h e e l s ,
and
can be
r e ñ c c t e d by m i r r o r s t o
t h e
proper
p a t h ,
o r
a l l o w e d t o f a l l d i r e c t l y
upon t h e w h e e l s .
T h e s e two f o r m s o f
t r a n s m i t t i n g
a p p a r a t u s
a r e shown a s t y p e s . A n y
p h o t o p h o n i c
t r a - n s
l n i t t e r
ofordinary
o r s u i t a b l e
c o n s t r u c t i o n
can
b e u s e d w i t h
t h e
improved r e c e i v e r .
I n F i g . l t h e r e c e i v e r
C
o n s i s t s o f a
f u n n e l
s h a p e d s o u n d - c h a m b e r , c , t h e i n t e r i o r
f l a r i n g
walls of which are
sm ok e d
or
covered with a
d e p o s i t
o t ' l a m p - b l a c k , œ .
r l ‘ h e
mouth i s
cov
e r e d w i t h
a
g l a s s
p l a t e , c ' , and a
s o u n d - c o n v e y ~
i n g
t u b e , c 2 , c o m m u n i c a t e s w i t h
t h e c o n t r a c t e d
p o r t i o n i n t h e r e a r .
Speech o r other sound u t
t e r e d
i n t o t h e tube a ’ ofthe
transmitterA
can
b e heard by l i s t e n i n g a t t h e t u b e
c 2 o t '
t h e r e
ceiver C. The istance over which
speech can
b e t r a n s m i t t e d
i n t h i s
wayand
t h e
d i s t i n c t n e s s
o t '
t h e sounds
reproduced
depend u pon t h e
e n
e r g y
o f t h e
beam
e m p l o y e d .
l n F i g . 2 t h e r e c e i v e r C c o n t a i n s a
p i e c e
o f
w i r e - g a u z e , c 3 , upon w h i c h
t h e
l a m p - b l a c k : v i s
d e p o s i t e d . ' l ‘ h e w a l l s o f
t h e
sound-chamber@
can a l s o
be smoked, a s shown, o r
n o t ,
a s de
s i r e d . The
sound
i s
r e c e i v e d
by t h e t u b e
c 2 ,
as
before.
I n
F i g s . 3
and 4the e c e i v e r i s a l a m p - b l a c k
c e l l , and
c o m p r i s e s
t h e g l a s s p l a t e o r
i n s u l a t
i n g s u p p o r t
d , t h e
i n t e r m e s h i n g
combs o r
c o n
d u c t o r s
e e ' ,
o f s i l v e r f i l m ,
t h e
b i n d i n g - p o s t s f
j , c o n n e c t e d
w i t h
t h e c o n d u c t o r s e e ’ , r e s p e c t ~
i v e l y ,
b y t h e m e t a l l i c p l a t e s g g ' , a n d t h e l a m p
black x.
I n f o r m i n g t h e c e l l t h e
s i l v e r i s
d e p o s i t e d i n
any
o r d i n a r y
o r s u i t a b l e
w a y . The
d e s i r e d
' p o r t i o n s a r e removed o r
scraped o i t '
by means
o t
a
t o o l
with
a
f i a t end. This t o o l can be
m a d e
l i k e a
c h i s e l ,
o r a punch with c o n i c a l
point
can be g r o u n d
o f f
or cut
a t
r i g h t angles
t o
the
a x i s ,
so as
to leave a t l a t
end
with a
d i a m e t e r e q u a l
t o
t h e
d e s i r e d width
o f t h e
s t r i p e t o b e r e m o v e d . The m e c h a n i c a l
r u l i n g
o r
s c r a p i n g
o f t h e p l a t e
can be
e a s i l y e f f e c t e d
by means o f
an
o r d i n a r y
l a t h e
p r o v i d e d
w i t h
a
s l i d e - r e s t . The t o o l i s held
i n
a frame sup
p o r t e d
b e t w e e n c e n t e r s . The l a t e i s c l a m p e d
t o a
b e d - p l a t e
beneath with
t h e s i l v e r e d s i d e
u p p e r m o s t ,
i n
s u c h
p o s i t i o n t h a t when t h e t o o l
i s p r e s s e d down
and
p e n e t r a t e s t h e
f i l m i t s
o p e r a t i n g
end e s t - s t l a t upon t h e s u r f a c e o f t h e
g l a s s .
The b e d -
p l a t e
c a r r y i n g t h e
s i l v e r e d
p l a t e
can b e
worked
l e n g t h w i s e o f t h e
l a t h e t o
r u l e
o r
scrape
t î '
the l i n e s
i n one
d i r e c t i o n ,
a n d
t h e n moved a c r o s s a t r i g h t a n g l e s t o
t h e
l e n g t h
t o b r i n g
t h e
p l a t e i n t o p o s i t i o n
f o r
s c r a p i n g a
new i n e .
I t
i s
not
necessary
t o
remove
the
t o o l
from
t h e p l a t e . The
l e n g t h w i s e
movement
under
the t o o l removes the f i l m so as
t o
form
the
s p a c e s between
t h e
t e e t h o f t h e
c o m b s , and
t h e t r a n s v e r s e
movementconnects
t h e s e s p a c e s
w i t h e a c h o t h e r a l t e r n a t e l y a t o p p o s i t e e n d s .
The b i n d i n g - p o s t s a r e f a s t e n e d t o t h e g l a s s
p l a t e i n any ordinary o r s u i t a b l e
way,
a n d a r e
i n
e l e c t r i c a l c o n n e c t i o n w i t h
t h e two
p a r t s o t '
t h e c o n d u c t i n g - f i l m .
' l ‘ o
a p p l y t h e c a r b o n t h e
s i l v e r e d s i d e o t '
t h e
g l a s s p l a t e i s smoked o v e r
a
s u i t a b l e
b u r n e r .
I n
F i g .
ñ
t h e s i l v e r f i l m i s
s c r a p e d
o í î ' i n t h c
f o r m o t ' a d o u b l e s p i r a l , l e a v i n g t h e c o n d u c t
o r s
c
e ’ . I n F i g . ( i v t h e
conductors
e
c ’ have
c u r v e d i n t e r m e s h i n g t e e t h . I n t h e s e ? g u r e s
the
lamp-black : r i s
shown
a s confined
t o the
spaces
between the conductors i n
order t o
show t h e
l a t t e r more c l e a r l y ; b u t i n p r a c t i c e
t h e c o n d u c t o r s w o u l d o r d i n a r i l y b e t h e m s e l v e s
c o a t e d .
I n F i g .
7
t h e
p o l e s o f t h e g a l v a n i c
c i r c u i t D
a r e connected
with
t h e binding-postsfj . A
m u s i c a l n o t e produced by t h e a c t i o n o f t h e i n
t e r m i t t e n t beam c a n
b e
h e a r d
by
a p p l y i n g
t h e .
telephone E o t h e e a r .
I n F i g . 8
t h e
l a m p / - b l a c k c e l l i s p l a c e d i n a
sound-chamber, , and s
c o n n e c t e d w i t h a b a t
t e r y i n t h e p r i m a r y c i r c u i t o t ’
t h e
i n d u c t i o n
c o i l
F ,
t h e
t e l e p h o n e - E b e i n g c o n n e c t e d
i n
t h e
s e c o n d a r y
c i r c u i t
o f
t h e
c o i l .
The chamber
C
h a s a
g l a s s
p l a t e , a s i n
F i g .
1 , t h r o u g h w h i c h
t h e r a d i a n t energy s
t r a n s m i t t e d ,
and
a
hear
i n g - t u b e ,
c 2 , f o r c o n v e y i n g t h e s o u n d - w a v e s
produced
i n
t h e r e c e i v e r t o t h e
e a r . Sounds
u t t e r e d i n t o t h e tube a ’
o f t h e
t r a n s m i t t e r can
b e h e a r d e i t h e r by l i s t e n i n g
a t
t h e t u b e
c 2
o r
by
means
o t ' t h e t e l e p h o n e E .
I t
i s
o b v i o u s t h a t v a r i o u s m o d i f i c a t i o n s may
b e
made
w i t - h o u t d e p a r t i n g f r o m t h e s p i r i t o f
t h e i n v e n t i o n ,
and t h a t
p a r t s o f
s a i d i n v e n t i o n
c o u l d
be used w i t h o u t
t h e o t h e r s . The f o r m s
o f c e l l s
used f o r selenium can be used with
l a m p - b l a c k ,
and
t h e
improved
c e l l
c a n
b e
e i n »
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p l o y e d
w i t h
any s u i t a b l e
form o f s e n s i t i v e
m e
dium; b u t
t h e m e t a l
composing t h e
c o n d u c t o r s
should
be
such
a s not
t o
be i n j u r i o u s l y a f f e c t e d
by
t h e a c t i o n o f
t h e s e n s i t i v e medium.
r l î h e
i n s u l a t i n g - p l a t e w i t h t h e r u l e d o r
s c r a p e d
s i l v e r
t i l m
thereon
can be
employed t o meas
u r e t h e
e l e c t r i c
c o n d u c t i v i t y o f v a r i o u s
sub
s t a n c e s , l i q u i d s ,
and
g a s e s
by
c o n n e c t i n g t h e
b i n d i n g - p o s t s w i t h t h e
p o l e s o t ’
a
galvanom
e t e r - c i r c u i t
and
i m m e r s i n g
t h e
p l a t e W i t h t h e
s u b s t a n c e
t o
be t e s t e d , o r c o v e r i n g t h e s i l
vered
s i d e
with the same. In
some cases
the
s i l v e r f i l m can be d e p o s i t e d on both s i d e s o f
t h e
p l a t e a n d
r u l e d
a s b e f o r e d e s c r i b e d .
T e l e p h o n i e t r a n s m i t t e r s
and
r e c e i v e r s can
b e formed by means
t '
a p p a r a t u s l i k e
t h e
lamp
b l a c k c e l l ; b u t t h e s e w i l l f o r m
t h e s u b j e c t
o f
s e p a r a t e
a p p l i c a t i o n s .
That p a r t
o f
t h e
i n v e n t i o n
which
r e l a t e s t o
t h e
conversion o f
t h e r a d i a n t
v i b r a t i o n s i n t o
e l e c t r i c a l
v i b r a t i o n s
i s
n o t
l i m i t e d
t o
lamp
b l a c k ,
b u t
i n c l u d e s o t h e r
f o r m s
o f c a r b o n , and
a l s o
o t h e r m a t e r i a l s
which o p e r a t e i n a sub
s t a n t i a l l y
s i m i l a r
manner
t o
l a m p - b l a c k .
Having now f u l l y
d e s c r i b e d our s a i d inven
t i o n
and
t h e
manner o f c a r r y i n g
t h e
same i n t o
e f f e c t , what we claim
i s
1 . I n a
p h o t o p h o n i c
r e c e i v e r , t h e
sound
chamber
f o r c o n t a i n i n g
t h e
s e n s i t i v e m e d i u m ,
having a
w a l l t r a n s p a r e n t
t o l i g h t o r
r a d i a n t
e n e r g y , b u t opaque r l e s s t r a n s p a r e n t
t o
s o u n d ,
s u b s t a n t i a l l y a s d e s c r i b e d .
y 2 . The
c o m b i n a t i o n
o f t h e
s o u n d - c h a m b e r ,
having a w a l l t r a n s p a r e n t t o r a d i a n t e n e r g y ,
b u t
opaque
o r l e s s t r a n s p a r e n t t o s o u n d , with
t h e
s e n s i t i v e
medium
t h e r e i n c o n t a i n e d , and
a sound conveyer
o r opening communicating
w i t h t h e i n t e r i o r o f s a i d
c h a m b e r ,
s u b s t a n t i a l l y
as described.
3 .
In a photophonic r e c e i v e r , the s e n s i t i v e
medium,
composed
o f v i b r a t o r y m a t e r i a l i n an
o p e n ,
p o r o u s , o r s u b d i v i d e d c o n d i t i o n , s u b s t a n
t i a l l y
a s
d e s c r i b e d .
4 . I n a p h o t o p h o n i c r e c e i v e r , a s e n s i t i v e me
dium o f
l a m p - b l a c k
o r s i m i l a r m a t e r i a l ,
s u b
s t a n t i a l l y a s d e s c r i b e d .
5 . Aphotophonic
e c e i v e r
having a s t h e s e n
s i t i v e medium a
d e p o s i t o f v i b r a t o r y m a t e r i a l
i n
a l o o s e , p o r o u s ,
s u b d i v i d e d ,
ñ o c c u l e n t ,
o r
spon
y
o n d i t i o n , s u b s t a n t i a l l y a s d e s c r i b e d .
6 .
I n
a p h c t o p h o n i c r e c e i v e r , t h e combina
t i o n o f a s e n s i t i v e medium c o n d u c t i v e
o f
e l e c
t r i c i t y , i n a l o o s e , p o r o u s , ' o r
s u b d i v i d e d
c o n d i
t i o n s u c h a s
l a m p - b l a c k ,
and c o n d u c t o r s f o r i n
c l u d i n g
t h e same i n au e l e c t r i c c i r c u i t , s u b s t a n
t i a l l y a s
d e s c r i b e d , s o t h a t r a d i a n t v i b r a t i o n s
c a n be t h e r e b y
c o n v e r t e d
i n t o e l e c t r i c v i b r a
t i o n s , a s s e t f o r t h .
7 .
r J ì h e
c o m b i n a t i o n
o f t h e l a m p - b l a c k o r
o t h e r
v i b r a t o r y
c o n d u c t i n g
m a t e r i a l
i n
l o o s e
p a r t i
c l e s ,
t h e r i g i d
o r s u b s t a n t i a l l y i n e x t e n s i b l e s u p
p o r t
o f
i n s u l a t i n g m a t e r i a l ,
and
c o n d u c t o r s by
which
the lamp-bla ck can be
included
i n an
e l e c t r i c
c i r c u i t , a s
s e t f o r t h .
8 . A c e l l A
c o m p r i s i n g s h e e t s ,
p l a t e s ,
o r
s t r i p s
o f
c o n d u c t i n g
m a t e r i a l , f i x e d o r
mounted upon
_ a
s u p p o r t
o f i n s u l a t i n g m a te r i a l ,
w i t h
t h e i r
e d g e s
o p p o s i t e
e a c h
o t h e r and
s e p a r a t e d b y
a
s u i t a b l e d i s t an c e ,
and
s e n s i t i v e c o n d u c t i n g ma
t e r i a l
i n
t h e s p a c e o r s p a c e s between s a i d e d g e s ,
s u b s t a n t i a l l y
a s
d e s c r i b e d .
9 .
A
u p p o r t
o f i n s u l a t i n g m a te r i a l , h a v i n g
comb-shaped
conductors
f i x e d o r mounted o n
s a i d s u p p o r t ,
a s
i n d i c a t e d ,
s o
t h a t t h e t e e t h o f
the
combs intermesh but
a r e
not
i n contact
W i t h e a c h o t h e r , s u b s t a n t i a l l y a s
d e s c r i b e d .
1 0 . A i l v e r e d p l a t e
having
t h e
s i l v e r f i l m
mechanically
u l e d o r s c r a p e d , a s de s c r i b e d , s o
a s
t o
l e a v e
p a r a l l e l
l i n e s
o r s t r i p e s o f
e q u a l
w i d t h , a n d w i t h s h a r p , c l e a n e d g e s , s u b s t a n t i a l l y
as s e t f o r t h .
1 1 . The i n s u l a t i n g - p l a t e having on one o r
both
s i d e s
a s i l v e r f i l m ruled
o r
s c r a p e d , a s de
s c r i b e d , s o a s t o
d i v i d e
the s i l v e r i i l m
i n t o
two
or more c o n d u c t o r s , i n combination with bind
i n
g - p o s t s c o n n e c t e d w i t h t h e
p a r t s
o f s a i d f i l m
o r f i l m s , s u b s t a n t i a l l y
a s s e t
f o r t h .
1 2 . The c o m b i n a t i o n
o f t h e i n s u l a t i n g - p l a t e
and r u l e d s i l v e r f i l m w i t h t h e lamp-black
o r
s e n s i t i v e
me di u m included
i n the
r u l e d o r
s c r a p e d s p a c e s i n
s a i d
t i l m , s u b s t a n t i a l l y a s
s e t f o r t h .
1 3 .
The o m b i n a t i o n , w i t h a g a l v a u i c c i r c u i t ,
o t ' a p h o t o p h o n i c c e l l
c o m p r i s i n g a
g l a s s
p l a t e
w i t h
r u l e d s i l v e r f i l m
t h e r e o n ,
l a m p b l a c k d e ~
p o s i t e d
i n
t h e r u l e d s p a c e s
i n
s a i d
ñ l m ,
and
o n
n e c t i o n s f o r c o m p l e t i n g t h e
g a l v a n i c
c i r c u i t
t h r o u g h
s a i d c e l l , s u b s t a n t i a l l y a s
d e s c r i b e d .
1 4 . r I l l e c o m b i n a t i o n , w i t h a
photophonic
c e l l ,
o f a n i n d u c t i o n - c o i l , e l e c t r i c
c o n n e c t i o n s
f o r
i n c l u d i n g s a i d
c e l l
i n one i r c u i t
o f s a i d
c o i l ,
and t e l e p h o n e ~ c i r c u i t c o n n e c t e d w i t h t h e o t h e r
c i r c u i t
o f
s a i d c o i l , s u b s t a n t i al l y a s d e s c r i b e d .
1 5 . A p h o t o p h o n i c r e c e i v e r c o m p r i s i n g a
sound~chamber having a w a l l t r a n s p a r e n t t o
r a d i a n t e n e r g y ,
but opaque
o r
l e s s transparent
t o
s o u n d , a c e l l
having
a v i b r a t o r y s e n s i t i v e
medium,
s u c h
a s
l a m p - b l a c k ,
e l e c t r i c a l
connec
t i o n s f o r c o n n e c t i n g s a i d c e l l i n an e l e c t r i c a l
c i r c u i t ,
a n d
a h e a r i n g - t u b e c o n n e c t e d
w i t h `
t h e
i n t e r i o r o f
s a i d
s o u n d - c h a m b e r , s u b s t a n t i a l l y
as
described.
I n t e s t i m o n y whereof we
have
s i g n e d t h i s
s p e c i f i c a t i o n i n
t h e
p r e s e n c e
o f
t w o s u b s c r i b
i n g w i t n e s s e s .
ALEXANDER GRAHAM BELL.
SUMNER TAIN'I‘ER.
W i t n e s s e s :
FHILIP MAURO,
A . P oLLoK .
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