- Why would a math teacher named Joseph Henry
invent the telegraph,
and didn't Samuel Morse invent the telegraph?
Well, I'll tell you, and along the way,
I'll talk about the importance
of insulating wire with petticoats,
dropping thousands of pounds of weights for fun,
the first doorbell,
a black assistant named Sam Parker
who couldn't get published or a patent if he wanted to,
and a very big missed opportunity.
Ready?
Let's go!
♪ Electricity, electricity ♪
- Joseph Henry had a hard life.
He was born in the backwoods of Albany, New York
in 1797 to poor Scottish immigrants.
His father was a notorious drunk who died from drink
when Henry was just nine years old.
Henry dropped out of school
and was an apprentice for a time with a watchmaker.
After a couple of years,
the watchmaker went out of business.
He then took odd jobs and dreamed of becoming an actor
while his mother took in boarders.
One boarder loaned the 16-year-old Henry
a book on science that inspired him to,
quote, "devote my life to the acquisition of knowledge."
When Henry was 19,
he received a full scholarship to further his education
at a high school called Albany Academy.
He studied mathematics, physics, and chemistry,
and supplemented his income with tutoring.
After graduation, he had a series of unrelated jobs,
but then in 1826,
he was hired as a math teacher
at the same school he went to 10 years earlier.
At first, Henry was glad of the offer
to work at the academy.
However, he really wants to do research
and quickly felt irritated spending half his time
with the drudgery of teaching algebra.
Then, one day, Henry read a paper.
An Englishman named William Sturgeon
had made a magnet with electricity
by wrapping wires around a soft iron bar.
Henry decided to use this method
to make the strongest magnet he could
with a single simple battery.
Henry first came up with the idea
of wrapping the wire with silk
made from strips of his wife's old petticoats,
making the first insulated wire.
With bare wire, the wire could not touch,
or it would short circuit and jump between wires,
instead of running through the wire.
Insulating wire allowed Henry to wrap the wires
around the iron very tightly together,
which vastly increased the magnetic field from the wires,
which makes a significantly stronger electromagnet.
At first, Henry did get a far stronger magnet
with more coils of wire.
However, after a while,
using more wire didn't make the magnet stronger.
It made it weaker.
Henry realized that the battery was producing
less and less current when he used the longer wire.
The longer the wire, the more resistance it had.
Henry then got the idea of wrapping a bar of iron
with nine separate coils of wire
that he could connect individually
or combine to the same battery.
He then experimented with attaching
different sections of the magnet to a simple battery.
He put a scale under the magnet
and measured the maximum weight it could support.
If only one coil was electrified,
it could support seven pounds.
If, however, he attached two to the same battery
in what we now call parallel,
so that the current goes through both coils
at the same time,
he could get the magnet to hold up to 145 pounds.
If he attached all nine coils,
he managed to lift 650 pounds.
Soon, Henry bested his own invention
and made an electromagnet that could hold over 2,000 pounds.
One of his favorite demonstrations
was to lift a very heavy object, then remove the battery
and have it fall down
with what must've been a terrifying bang,
which according to Henry, quote,
"never fails to produce
a great sensation among the audience,
as, before the fall, they can scarcely believe
that the magnet supports the weight."
Henry wondered how far he could separate the battery
in the electromagnet.
First, he scaled down the electromagnet,
and made a simple electromagnet
that was tightly wound with insulated wire
and was placed near a metal bar on a pivot.
When the electromagnet was electrified,
it moved the bar, which rung a bell.
Basically, it was the first doorbell.
Henry then spooled out wires
throughout the upper rooms of the academy,
and managed to make the bell ring
with a signal from a battery over a mile away.
More than a doorbell, Henry had invented the telegraph.
Amazingly, Henry recognized he invented the telegraph
at the time.
See, people have been trying to use electricity
to send signals long distances since the 1700s.
By 1820, a Danish man named Oersted
had determined that current in a wire
would cause a nearby compass needle to turn.
After Oersted, multiple people tried to use this
to transmit signals long distance,
a system they called electric telegraph.
When William Sturgeon first coiled wire around an iron bar
to make the first electromagnet in 1824,
his friend and mentor, Peter Barlow,
tried to use it to make an electromagnetic telegraph,
but found that it didn't work for more than 200 feet
and gave it up.
Therefore, when Henry made his more powerful electromagnet
and long distance communication in 1831,
he added that it is, quote,
"directly applicable to Mr. Barlow's project
of forming an electromagnetic telegraph."
Henry's publication in 1831 won him acclaim,
and he was offered a job as a professor
at Princeton University, the very next year,
despite the fact that he admitted
that he was not a graduate of any college.
At Princeton, Henry made a combination
of both his bell ringing
and his heavy-lifting electromagnet.
He built a battery connected for miles to a small coil.
Instead of the coil ringing a bell,
the coil pulled a switch that closed the circuit
with another battery that was next to a large electromagnet.
In this way, Henry could remotely lift and drop
an astonishing weight from a large distance.
So, Henry had not only invented the telegraph.
He'd also invented the relay,
an electromagnetic switch that would connect a new circuit,
but could extend a telegraph for as long as one wanted to.
The next year, Henry installed a telegraph
where he draped wires on trees
between his laboratory and his house
to tell his wife when he wanted lunch.
He used a single wire and then grounded the other end
for return passage.
This is the first time that
the Earth was used as a conductor for a telegraph,
an important feature for long distance telegraphs.
Henry's work at Princeton was greatly aided
when he was assigned an assistant,
a free black man named Sam Parker.
Parker was a bit of a campus character.
He was known to sneak in late night dinners to students
in exchange for old suits,
and was rumored to own over a hundred pairs of suits,
which he changed multiple times a day.
Henry wrote often of his appreciation for Parker's work
and said he was indispensable.
For example, in 1842, Henry wrote that
his work was delayed for two weeks because Parker was sick.
However, like most white people at the time,
Henry treated his assistant like a child,
and although he was anti-slavery, by today's standard,
Joseph Henry would be considered a racist.
The students were even more racist.
They loved to watch Parker do electrical experiments,
but it was a dangerous time to be a black person in America,
especially one that was known to put on airs.
We only know about Sam Parker
through the writings of Joseph Henry,
and through the biography of a Princeton graduate
named Edward Shippen, whose picture we have, of course.
Shippen described how Parker
was considered by the students to be, quote,
"one of the most important persons in Princeton."
While he also described how he and his fellow students
disliked Parker's independence, or "impudence,"
as he would put it.
Years later, Shippen gleefully and maliciously
described how Parker's behavior improved
when Parker was, and these are Shippen's words, quote,
"thoroughly flailed by a stalwart North Jersey man."
Although Henry, with the possible help of Parker,
invented the telegraph, they never patented their ideas.
Henry's friends actually encouraged him to get a patent
as early as 1831,
but he decided it was incompatible with, quote,
"the dignity of science," to do so,
or at least that's what he said years later
after he found out how powerful, influential,
and financially successful the telegraph would be.
Sam Parker never patented anything either,
but for different reasons.
First, it is unclear exactly what Parker discovered,
as no scientific journal at the time
would publish the research of a black servant assistant.
Also, if he did try to patent these ideas,
he could never have afforded the $30 patent fee,
as he only earned $48 a year.
Instead, the patent and the fame and the money
went to a truly loathsome person,
Samuel Morse of the Morse Code,
and that story is next time on
"The Secret History of Electricity."
♪ Electricity, electricity ♪
- Thanks for watching my video.
Please remember to give it a nice thumbs up.
Also make sure to check out the last video
about William Sturgeon inventing the electromagnet
and how an electromagnet works,
and also make sure to check out the next one
about Samuel Morse stealing the telegraph.
It's a doozy.
Okay, have a good day.
(upbeat music)