US patent 241909 to A.G. Bell and S. Tainter, entitled “Photophonic Receiver”, issued 1881

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 .


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

c.


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 .


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


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


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

9 0

9 5

IOO

1 0 5

IIC

1 1 5

120


5/7

IO

30

3 5

5 0

5 5

6 5

241 909 3

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


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

[OO

o :

IZO


6/7

IO

2 5

30

3 5

4 5

50

5 5

4

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


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


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


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


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


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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Documents

US patent 241909 to A.G. Bell and S. Tainter, entitled “Photophonic Receiver”, issued 1881