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Speaker 1: Welcome to Stuff You Missed in History Class, a production

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Speaker 1: of I Heart Radio. Hello and welcome to the podcast.

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Speaker 1: I'm Tracy V. Wilson and I'm Holly Fry. We have

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Speaker 1: gotten various requests over the last several months to talk

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Speaker 1: about people who discovered or accomplished something during some kind

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Speaker 1: of a pandemic or quarantine. It's not surprising that we're

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Speaker 1: getting requests like this, uh by really coincidence. Today's topic

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Speaker 1: almost fits with that. Abu Ali al Hassan abenel Hassan,

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Speaker 1: ebenel hate Them, whose name has also been latinized as

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Speaker 1: al Hassan or al Hasen, made massive contributions to the

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Speaker 1: world's understanding of light and vision through experiments that he

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Speaker 1: did during a prolonged house arrest. That house arrests took

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Speaker 1: place in Cairo in the early eleventh century. He was

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Speaker 1: one of the pa maths of the Islamic Golden Age,

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Speaker 1: and in addition to his work on optics, he also

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Speaker 1: wrote about medicine and philosophy and astronomy, math, ethics, on

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Speaker 1: and on. He's been on my list for a really

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Speaker 1: long time, and it was only after really getting into

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Speaker 1: it that I was like, oh, this almost fits with

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Speaker 1: this thing that people have been asking us to do

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Speaker 1: for the last seven or eight months. Hooray uh. So.

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Speaker 1: The Islamic Golden Age was a period of intellectual, cultural,

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Speaker 1: and economic flourishing that spanned from about the eighth through

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Speaker 1: the fourteen centuries. We have talked about figures from this

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Speaker 1: era a few times on the show before, including even

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Speaker 1: Sina also called Avicenna, who was a physician and an astronomer,

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Speaker 1: and al Karismi, who is known as the father of algebra.

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Speaker 1: The Abbasid Caliphate, whose territory covered a lot of northern Africa,

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Speaker 1: the Middle East, and western Asia, selected Baghdad as its

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Speaker 1: capital in the eighth century. Baghdad was one of the

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Speaker 1: wealthiest cities in the world, and it was ideally positions

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Speaker 1: to bring in scholars and texts from all around Europe

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Speaker 1: and Asia, as well as from within the Kliphates territory.

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Speaker 1: The Abbasid dynasty was also really strong and prosperous, pretty stable,

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Speaker 1: so it could focus on and encourage learning and discovery,

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Speaker 1: rather than, for example, needing to put all of its

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Speaker 1: resources toward defending itself from its neighbors. Although Baghdad was

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Speaker 1: the heart of all of this Artists, scientists, and intellectuals,

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Speaker 1: including Christian and Jewish scholars spread all through the Muslim

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Speaker 1: world during this era, and other cities and intellectual centers

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Speaker 1: were founded as well. One was Cairo, established by the

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Speaker 1: Fatimid Caliphate as its capital in nine sixty nine. The

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Speaker 1: Fatimid Caliphate also built the Alazar Mosque and University complex

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Speaker 1: in Cairo not long after founding the city. Before this point,

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Speaker 1: the Fatimid dynasty had controlled parts of Northern Africa and Sicily,

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Speaker 1: and the establishment of Cairo was part of its ongoing

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Speaker 1: efforts to take control of it's now Egypt. The Fatimid

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Speaker 1: Caliphate was part of the Ismaili sect of Shia Islam,

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Speaker 1: while the Abbasid Caliphate was Sunni, so when Cairo was founded,

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Speaker 1: this was part of the Fatimid dynasty's efforts to try

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Speaker 1: to expand both its territory and its religious influence and

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Speaker 1: then thus the spread of Shia Islam. Cairo was where

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Speaker 1: Eben al Hathum would go on to do most of

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Speaker 1: his intellectual and scientific work, but he was born in Basra, Persia,

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Speaker 1: which is now a rock around because of his birthplace.

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Speaker 1: Sometimes you'll also see Al Basri included as part of

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Speaker 1: his name. Some sources also suggest that there were really

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Speaker 1: two different Ibben al Hathems, because one early source lists

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Speaker 1: his first name as Mohammed, but it was also common

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Speaker 1: to name newborn boys Mohammed and to add another name

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Speaker 1: as the child got older, at which point most sources

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Speaker 1: would differ to that new name. We really don't know

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Speaker 1: all that many details about Eban al Hathem's biography, although

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Speaker 1: he did write an autobiography that is not focused on

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Speaker 1: the details of his life at all. It's more about

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Speaker 1: his intellectual development. The two earliest accounts of his life

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Speaker 1: date back to the thirteenth century, and their brief and

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Speaker 1: also they contradict one another in various details. It is

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Speaker 1: generally agreed that he studied in Baghdad, and that this

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Speaker 1: included an extensive study of religion. This region of the

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Speaker 1: world was home to the Shiite and Sunni branches of Islam,

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Speaker 1: as well as Christianity and Judaism, and then within those

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Speaker 1: there were also various divisions and sects. In studying all

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Speaker 1: of this, Iban al Hatham came to the conclusion that

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Speaker 1: none of these religions really expressed the truth, and that

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Speaker 1: the truth itself was its own religion, so he decided

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Speaker 1: to devote himself to science. To be clear, though this

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Speaker 1: wasn't a rejection of everything that might be associated with religion.

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Speaker 1: He wrote quote, I constantly sought knowledge and truth, and

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Speaker 1: it became my belief that for aiming access to the

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Speaker 1: effulgence and closeness to God, there is no better way

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Speaker 1: than that of searching for truth and knowledge. Before making

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Speaker 1: this decision, he had trained for some kind of civil

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Speaker 1: service position, perhaps as a judge or a mayor, but

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Speaker 1: he left that position and immerged himself in the works

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Speaker 1: of previous figures like Aristotle and Galen. He eventually established

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Speaker 1: himself as a renowned scholar. One of the most widely

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Speaker 1: repeated stories about ibanel Hathem's life has to do with

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Speaker 1: a project to try to control the waters of the

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Speaker 1: Nile River. The river's annual flood cycle enriched the soil

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Speaker 1: of the Nile River valley with silt, but it could

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Speaker 1: also be incredibly destructive, and, as the story goes, Al Hakim,

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Speaker 1: who was at the time the caliph of the Fatimid dynasty,

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Speaker 1: wanted to find a way to control the river's floods

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Speaker 1: through hydro engineering. Either he had heard of ebanl hate

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Speaker 1: Them's reputation or Ibanel hate Them had volunteered for this project.

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Speaker 1: Either way, though, but I'll Hathem went to Cairo to

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Speaker 1: start working on this. The logical place to try to

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Speaker 1: control the river was at the Niles First Cataract, near

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Speaker 1: a swan, but after Ibanel Hatham got there, he eventually

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Speaker 1: concluded that the project was just impossible. Again, there is

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Speaker 1: some lack of clarity here, whether it was because the

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Speaker 1: materials available weren't sufficient, or because he thought damning the

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Speaker 1: river would cause flooding upstream that would destroy ancient temples

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Speaker 1: and other monuments there, or if it was because it

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Speaker 1: was just beyond his abilities as an engineer. Whatever happened,

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Speaker 1: this project was a failure. This really should not reflect

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Speaker 1: on his ability, though it would be almost one thousand

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Speaker 1: years before anyone managed to damn the Nile River. Abanel

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Speaker 1: hath Them was appointed to a post within Al Hakim's administration,

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Speaker 1: but before long he started to suspect that his life

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Speaker 1: might be in danger. Al Hakim had come to power

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Speaker 1: at the age of eleven, and at this point he

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Speaker 1: would have been in power for about fifteen years, and

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Speaker 1: during that time he had developed a reputation for being

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Speaker 1: a zealous, unpredictable, and cruel ruler. Under his rule, anyone

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Speaker 1: who wasn't a Shiite Muslim faced religious persecution, and some

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Speaker 1: of his other policies seemed simultaneously harsh and random, like

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Speaker 1: ordering that all the dogs in a city be killed

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Speaker 1: because he didn't like their barking. Iban L Hatham had

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Speaker 1: failed to find a way to control the waters of

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Speaker 1: the Nile, and he feared that the punishment for that

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Speaker 1: failure might be severe, so he feigned madness and he

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Speaker 1: was placed under house arrest. He stayed there for about

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Speaker 1: ten years until Al Hakim mysteriously disappeared while out for

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Speaker 1: a walk one night in ten twenty one. At that point,

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Speaker 1: iban L Hatham used the work that he had been

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Speaker 1: doing during those years, which we're going to get into

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Speaker 1: you in a moment, to convince authorities that he was

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Speaker 1: in his right mind and that he could be released.

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Speaker 1: Gibanell Hatham stayed in Cairo after all of this, living

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Speaker 1: near the university and Mosque complex. He made a living

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Speaker 1: copying manuscripts, which meant that he became really deeply familiar

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Speaker 1: with the range of scholarly and religious texts that he

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Speaker 1: was copying, and during his lifetime he wrote at least

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Speaker 1: a hundred works of his own. Some sources say as

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Speaker 1: many as two hundred fifty five of them have survived

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Speaker 1: until today. And these works include writings on astronomy, meteorology, medicine,

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Speaker 1: and anatomy, especially the anatomy of the eye, including other subjects.

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Speaker 1: But the biggest and most recognized contribution was to optics,

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Speaker 1: and we're going to get into that after we pause

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Speaker 1: for a sponsor break. Most of the ideas that informed

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Speaker 1: ibn All Hate Them's work on vision and optics came

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Speaker 1: from Greece, and I find some of the Greek world

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Speaker 1: ideas about how vision worked to be delightful. They are

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Speaker 1: indeed so. For example, several Greek philosophers, including Lucippus, Democratis

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Speaker 1: and Epicurus, favored the concept of intromission, or the idea

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Speaker 1: that something that objects were emitting was entering the eye. Specifically,

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Speaker 1: they were emitting idola. These were thought to be tiny,

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Speaker 1: tiny replicas of objects that flew off of everything in

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Speaker 1: every direction. The entry of these idola into the eye

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Speaker 1: was what allowed people to see. I'm just gonna say,

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Speaker 1: if you want to go google this make sure to

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Speaker 1: include the word vision or I after intromission, because it

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Speaker 1: also has another meeting that is related to human reproduction.

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Speaker 1: One piece of evidence citing for this idea of tiny

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Speaker 1: replicas of things flying around was that sometimes when you

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Speaker 1: look at a person's pupil, you can see a little

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Speaker 1: tiny image of what they're looking at and their pupil.

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Speaker 1: It's almost like a tiny, tiny version of that thing

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Speaker 1: they're looking at might actually be inside of there. The

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Speaker 1: logic is sound, uh, if not supported by actual science. Uh.

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Speaker 1: This idea did raise some questions though, like, if there

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Speaker 1: were tiny replicas of everything in the world flying around

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Speaker 1: all the time, wouldn't they collide with or pass through

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Speaker 1: each other causing some kind of distortion or interference. And

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Speaker 1: even if these replicas were so thin as to basically

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Speaker 1: be one dimensional, if they're coming from every object in

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Speaker 1: the world, that is still a lot of material floating around.

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Speaker 1: And then once they got into the eye, how did

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Speaker 1: that translate into actually seeing? And then what happened to

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Speaker 1: the idola after it traveled into the eye. How was

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Speaker 1: it possible for giant objects like mountains and tiny objects

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Speaker 1: like ants to both of its idola that were the

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Speaker 1: right size to enter the eye. These are all natural questions,

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Speaker 1: and they go on and on and on. Other philosophers

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Speaker 1: include Plato and Euclid, were proponents of a different theory

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Speaker 1: called extra mission and extra mission. The eyes themselves were

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Speaker 1: emitting something described as light or fire or numa depending

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Speaker 1: on who you're reading. This emission from the eyes struck objects,

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Speaker 1: and that was what allowed the viewer to see them.

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Speaker 1: One piece of evidence cited a support for this whole

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Speaker 1: idea was the fact that sometimes animals eyes seemed to

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Speaker 1: glow in the dark, the idea being that this glow

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Speaker 1: was something from their eyes that was allowing them to see.

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Speaker 1: Euclid's explanation for this concept included the idea that the

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Speaker 1: emission took the form of a cone with the pointed

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Speaker 1: part at the viewer's eye, which explains how objects look

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Speaker 1: bigger when they are close up and smaller when they're

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Speaker 1: farther away. Some philosophers also reasoned that this force being

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Speaker 1: emitted from the eye interacted with a force that was

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Speaker 1: also being emitted by the objects, so sort of a

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Speaker 1: hybrid of these two concepts. Ptolemy supported Euclid's ideas on this,

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Speaker 1: with the addition that the numa was actually continuous. Galen

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Speaker 1: supported the idea of extremission as well, believing that the

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Speaker 1: numa originated in the brain and traveled down the optic

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Speaker 1: nerve before going out through the eye. But as was

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Speaker 1: the case with intermission, this idea of extremission also raised

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Speaker 1: a number of questions. As one example, how could something

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Speaker 1: emitted by a person's eye travel all the way to

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Speaker 1: the stars and wouldn't that take a long time? Why

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Speaker 1: wasn't there a delay when looking at the night sky

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Speaker 1: before the stars became visible. The various philosophers who detailed

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Speaker 1: their ideas of vision also wrote about visual phenomena that

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Speaker 1: just didn't seem to make sense, like the way objects

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Speaker 1: appeared to be bent when you view them through a

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Speaker 1: layer of still water, or the fact that the moon

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Speaker 1: looks so much bigger when it's near the horizon, or

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Speaker 1: iridescent bird feathers or plants, or mirrors in general, and

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Speaker 1: the various ways that mirrors can distort the objects that

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Speaker 1: they're reflecting. For the most part, these were interpreted as

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Speaker 1: errors in vision, not as phenomena that had some kind

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Speaker 1: of rational explanation on their own. Ibanel Hathem had access

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Speaker 1: to many of these ideas, including a portion of Ptolemy's

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Speaker 1: optics that had been translated into Arabic and commentaries that

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Speaker 1: had been written in or translated into Arabic. This included

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Speaker 1: work from some of his own contemporaries, including Ibn Saul,

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Speaker 1: a Persian mathematician who built on Ptolemy's work to study

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Speaker 1: lenses and refraction. Yeah, these these ideas and variations on them,

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Speaker 1: we're just really the commonly understood explanation for how light

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Speaker 1: and vision worked. During his house arrest, in addition to

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Speaker 1: working from these texts, Emanel Hathem did experiments with light.

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Speaker 1: He observed how it passed through different substances like water

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Speaker 1: and smoke, and he also worked with lenses and mirrors.

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Speaker 1: At some point, as the story goes, he walked into

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Speaker 1: a darkened room where a tiny, tiny hole had formed

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Speaker 1: in one of the window shades. Light from that hole

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Speaker 1: struck the wall on the opposite side of the room,

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Speaker 1: and when he examined that spot of light, he realized

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Speaker 1: he was seeing a tiny, inverted view of the world

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Speaker 1: outside the window. The term camera obscura would not be

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Speaker 1: coined until the seventeenth century, but that's basically what this was.

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Speaker 1: Eben L. Hatham built a version of the room in miniature,

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Speaker 1: essentially a pinhole camera, and incorporated that into his experiments

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Speaker 1: as well. He used complex arrangements of candles to study

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Speaker 1: how the images from the pinhole changed from one arrangement

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Speaker 1: to the next. To be clear, there was not film

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Speaker 1: involved in this. It was just the light that he

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Speaker 1: was seeing and what he was seeing in that light.

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Speaker 1: Based on all of this work, Eban L. Hatham drew

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Speaker 1: several important conclusions. One was that light always travels in

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Speaker 1: straight lines. He described the thinnest possible amount of such

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Speaker 1: light as the least light, which Isaac Newton would later

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Speaker 1: describe as a ray evan I'll hate them. Also concluded

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Speaker 1: that light itself was invisible and colorless, but that its

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Speaker 1: existence allowed people to see because of the way it

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Speaker 1: interacted with the eyes. In addition to all the experimental

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Speaker 1: work he did with the camera obscura, he also sided

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Speaker 1: the fact that looking directly out of bright light can

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Speaker 1: be painful and can cause a person to see after

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Speaker 1: images when they look away. Can also damage the eyes. Clearly,

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Speaker 1: looking at light directly affected the eye. Eban L. Hatham's

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Speaker 1: explanation of vision was that invisible light reflected off of

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Speaker 1: every point of every surface in every direction, and once

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Speaker 1: that reflected light entered a person's eye, it allowed them

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Speaker 1: to see. He also concluded that this reflected light was

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Speaker 1: entering the eye at every angle, but that only the

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Speaker 1: light that struck the lens straight on perpendicular to the

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Speaker 1: lenses surface actually passed through the pupil to be used

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Speaker 1: by the eye. Each perpendicular ray of light made one

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Speaker 1: point of a corresponding image on the back of the eye.

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Speaker 1: The optic nerve carried that image to the brain, where

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Speaker 1: it was combined with the image from the other eye.

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Speaker 1: So there are some details of this that are not

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Speaker 1: quite there. For example, the cornea and the lens of

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Speaker 1: the eye work together to help focus the image that's

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Speaker 1: being seen, rather than it being a matter of only

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Speaker 1: perpendicular rays of light making an image point by point

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Speaker 1: on the back of the eye. Even so, though there

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Speaker 1: is a lot about this explanation that is right or

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Speaker 1: really close to right, and it is way way more

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Speaker 1: correct than intermission or extra mission. Along with the detailed

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Speaker 1: diagrams of the anatomy of the eye, even L. Hatham's

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Speaker 1: explanation for how light and vision worked were the most

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Speaker 1: accurate and most complete for more than five hundred years

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Speaker 1: after he developed all this. We're going to talk about

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Speaker 1: some of Inban L. Haytham's other work after we pause

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Speaker 1: once again for a quick sponsor break. Gibbon L hate

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Speaker 1: Them turned his study of light and vision into a

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Speaker 1: seven volume work called The Treasury of Optics. The first

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Speaker 1: three volumes were dedicated to the topic of site, the

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Speaker 1: next three to reflection, and the last to refraction. The

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Speaker 1: volumes on site also included, as we mentioned earlier, extensive

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Speaker 1: work on the anatomy of the eye, and for about

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Speaker 1: six hundred years after he finished this work, this whole

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Speaker 1: total seven volume thing was the most extensive, detailed and

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Speaker 1: correct work on vision and optics in the world. The

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Speaker 1: next major work on this subject was Johannes Kepler's Astronomia

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Speaker 1: Parts Optica or Optical Part of Astronomy, which came out

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Speaker 1: in sixteen o four, and it wasn't until the nineteenth

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Speaker 1: century that his explanation of binocular vision was really improved on.

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Speaker 1: But as we mentioned at the top of the show,

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Speaker 1: like many other scholars of the Islamic Golden Age, even

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Speaker 1: al Hathen was a polymath. In addition to his extensive

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Speaker 1: work on optics, he also published treatises on astronomy, mathematics, medicine,

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Speaker 1: all kinds of stuff. So we're going to hit some

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Speaker 1: of the highlights. In addition to that seven volume work

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Speaker 1: on optics, even All Hate Them, also published a lot

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Speaker 1: of other work on light and humans perception of it.

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Speaker 1: This included on the light of the Moon, on the

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Speaker 1: Halo and the Rainbow, on the shape of the eclipse,

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Speaker 1: and a discourse on light. He also wrote on the

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Speaker 1: subject of burning lenses, that is, lenses that can focus

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Speaker 1: light to the point that it can cause objects to ignite.

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Speaker 1: Some of his writing on lenses also suggests that he

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Speaker 1: understood their potential to magnify, although lenses made to actual

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Speaker 1: we do that weren't developed until the thirteenth century. He

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Speaker 1: also discussed and wrote a solution for a problem that

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Speaker 1: Ptolemy had first articulated in about the year one fifty,

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Speaker 1: which is now known as al Hasan's problem or al

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Speaker 1: Hasan's Billiard problem. Essentially, here's how it goes. Imagine a

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Speaker 1: source of light and a spherical mirror. How can you

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Speaker 1: find the exact point on the mirror that will reflect

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Speaker 1: light into the eye of an observer. It's called the

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Speaker 1: billiard problem because you can ask the same basic question

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Speaker 1: using billiard balls and at exactly what point one would

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Speaker 1: need to strike a ball in order for it to

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Speaker 1: bounce from the edge of the table and strike another ball.

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Speaker 1: Even al hathem solution to this problem involved a series

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Speaker 1: of six geometric proofs. Even al Hathem also wrote on astronomy,

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Speaker 1: including on the configuration of the world, and he combined

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Speaker 1: astronomy and optics in the trace on the Moon's face.

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Speaker 1: At that point, people didn't really know what exactly caused

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Speaker 1: the dark path turn that is on the surface of

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Speaker 1: the Moon when it's feed from the Earth, but as

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Speaker 1: was the case with how vision works, there were lots

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Speaker 1: of ideas for that. In the Trace on the Moon's face,

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Speaker 1: Even I'll Hate Them rules out the idea that these

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Speaker 1: are shadows cast by features on the Moon, because such

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Speaker 1: shadows would shift based on the angle of the light

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Speaker 1: hitting the Moon. He also rules out the idea that

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Speaker 1: they were a reflection of things on the Earth because

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Speaker 1: those reflections would also change based on where on the

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Speaker 1: Earth you were when you observed the moon. They do

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Speaker 1: not change. They're the same from everywhere. He concludes that

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Speaker 1: the moon's dark areas are dark because they're made from

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Speaker 1: a material that doesn't reflect as much light as the

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Speaker 1: rest of it, which is true. Yeah, this was a

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Speaker 1: long time before again, like early sixteen hundreds is when

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Speaker 1: people first observed the Moon through a telescope, So he's

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Speaker 1: way ahead of the game here even l. Hatham also

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Speaker 1: wrote about why it is that the Moon looks so

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Speaker 1: big when it's low on the horizon, concluding that thick

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Speaker 1: vapors in the Earth's atmosphere might be a factor, but

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Speaker 1: that it was mostly just a matter of perception. He

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Speaker 1: also wrote about mathematics, preferring number theory and geometry over algebra.

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Speaker 1: In terms of geometry, he wrote about squaring the circle,

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Speaker 1: that is, figuring out how to create a square that

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Speaker 1: would be the same area as a corresponding circle. It

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Speaker 1: doesn't appear that he totally solved this problem. He wrote

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Speaker 1: a treatise on the subject that still survives and doesn't

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Speaker 1: include the solution. It refers to a forthcoming treatise that

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Speaker 1: has not been unearthed yet at this point and may

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Speaker 1: not have survived until today. He also wrote Doubts concerning Ptolemy,

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Speaker 1: which I Just Love as a title, uh that analyzed

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Speaker 1: the second century mathematicians major works and corrected what he

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Speaker 1: saw as errors and inaccuracies in them. In addition to

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Speaker 1: work on optics and astronomy and other work on physics

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Speaker 1: and math, IM and L. Hatham was a practicing physician

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Speaker 1: and surgeon, including developping a method for removing soft cataracts

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Speaker 1: from the eye using a hollow needle. In the vast

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Speaker 1: majority of his work And and I'll Hate Them followed

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Speaker 1: a method that was really really similar to the scientific

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Speaker 1: method as it's described today. He would make an observation,

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Speaker 1: form a hypothesis, and then test that hypothesis using experiments.

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Speaker 1: These experiments allowed him to gather data that he could analyze,

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Speaker 1: with that analysis either proving or disproving the hypothesis. He

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Speaker 1: was by far not the first person to include experiments

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Speaker 1: in their work, but a lot of earlier scholars weren't

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Speaker 1: so much as conducting an experiment as they were performing

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Speaker 1: a demonstration. They were kind of choosing their experiment in

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Speaker 1: order to illustrate what they already thought was the right answer.

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Speaker 1: And and I'll Hate Them, on the other hand, was

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Speaker 1: designing experiments to test a hypothesis. For that reason, sometimes

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Speaker 1: he's called the father of the scientific method or the

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Speaker 1: first scientist even a. Hatham died in Cairo in about

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Speaker 1: ten forty at the age of roughly seventy four. In

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Speaker 1: the decades after his death, the Turkish cell Joke dynasty

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Speaker 1: invaded Baghdad and Crusaders invaded the region around Cairo. These

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Speaker 1: and other factors may have kept Evan l Hathem's works

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Speaker 1: from being widely disseminated until the late thirteenth century. That

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Speaker 1: was when mathematician Kamal al Dean al Farsi published an

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Speaker 1: interpretation of his work on optics. In the thirteenth century,

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Speaker 1: someone also translated The Treasury of Optics into Latin. That

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Speaker 1: translation went on to influence the work of people like

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Speaker 1: Roger Bacon, Johannes Kepler, Leonardo da Vinci, and Renee des Cartes.

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Speaker 1: Yeah that there were other translations later that we know

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Speaker 1: who did them, but that first one is kind of

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Speaker 1: a mystery. Evan al Haytham's work, translated into Latin or

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Speaker 1: summarized and interpreted, was widely circulated in thirteenth century Europe.

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Speaker 1: Credited to this latinized name of al Hassan or al

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Speaker 1: Hazen I mean evil. European scholars nicknamed him ptolemais Secundus

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Speaker 1: or the second Ptolemy. He was well known enough that

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Speaker 1: he's referenced in the thirteenth century poem The Romando la

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Speaker 1: Rose and in the Squire's Tale from Jeffrey Chaucer's Canterbury Tales.

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Speaker 1: In the fourteenth century, of An al Hathem's work also

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Speaker 1: started to be translated into Italian and affecting people's understanding

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Speaker 1: of the world there In To mark the one thousandth

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Speaker 1: anniversary of ibanel Hathems seven volume work on optics, UNESCO

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Speaker 1: had the International Year of Light. This was a year

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Speaker 1: of programs and events related to light science and light technologies.

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Speaker 1: A short film was made as part of this called

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Speaker 1: one thousand and one Inventions of the World of ibanel Hatham.

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Speaker 1: It combines live action and animation and it was Egyptian

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Speaker 1: actor Omar Sharif's final film role. For the International Year

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Speaker 1: of Light. Ibanel Hathem story was also made into a

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Speaker 1: National Geographic kids book. And we will end with a

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Speaker 1: quote from M. L. Hatham from his doubts about Ptolemy quote,

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Speaker 1: the seeker after truth is not one who studies the

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Speaker 1: writings of the ancients, and, following his natural disposition, puts

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Speaker 1: his trust in them. But rather the one who suspects

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Speaker 1: his faith in them and questions what he gathers from them,

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Speaker 1: the one who submits to argument and demonstration, and not

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Speaker 1: the sayings of human beings whose nature is fraught with

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Speaker 1: all kinds of imperfection and deficiency. Thus, the duty of

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Speaker 1: the man who investigates the writings of scientists, if learning

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Speaker 1: the truth is his goal, is to make himself an

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Speaker 1: enemy of all that he reads, and, applying his mind

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Speaker 1: to the core and margins of its content, attack it

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Speaker 1: from every side. He should also suspect himself as he

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Speaker 1: performs his critical examination of it, so that he may

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Speaker 1: avoid falling into either prejudice or leniency. Oh the trickiest part, right,

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Speaker 1: that's that's uh yeah, I um as I was. I

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Speaker 1: love this quote, and I also feel like in the

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Speaker 1: world we're living in, we definitely see cases of people

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Speaker 1: definitely doing the first part of questioning the work that

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Speaker 1: has come before, but not as much the second part

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Speaker 1: about examining their own selves to make sure that there

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00:26:16,960 --> 00:26:21,159
Speaker 1: is not prejudice or leniency involved in what they're doing.

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00:26:23,480 --> 00:26:26,679
Speaker 1: Do you have a listener mail I do. This is

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00:26:26,760 --> 00:26:29,879
Speaker 1: from Jessica, and Jessica wrote, Hi, Tracy and Holly, I

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00:26:29,920 --> 00:26:32,399
Speaker 1: was listening to your episode on the Demon Core and

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00:26:32,440 --> 00:26:36,720
Speaker 1: you mentioned Operation Crossroad. Funnily, this wasn't the first time

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00:26:36,720 --> 00:26:38,840
Speaker 1: I'd heard of it, and the story behind why it

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00:26:38,920 --> 00:26:41,000
Speaker 1: is kind of humorous. At one point, I was going

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00:26:41,040 --> 00:26:43,439
Speaker 1: through old pictures with my grandfather of his time in

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00:26:43,480 --> 00:26:46,040
Speaker 1: the Second World War serving in the Navy on the

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00:26:46,119 --> 00:26:50,000
Speaker 1: USS Columbus. We were looking at normal naval ship life

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00:26:50,040 --> 00:26:52,800
Speaker 1: until we turned the page and there were multiple pictures

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00:26:52,840 --> 00:26:57,400
Speaker 1: of atomic mushroom clouds. Absolutely not what I was expecting

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00:26:57,440 --> 00:27:00,440
Speaker 1: to find, especially when he told me that he himself

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00:27:00,480 --> 00:27:04,399
Speaker 1: had taken the pictures. According to him, his ship was

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00:27:04,440 --> 00:27:06,960
Speaker 1: part of the process to determine what would still be

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00:27:07,080 --> 00:27:10,320
Speaker 1: functional on a ship after a nuclear bomb was detonating

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00:27:10,400 --> 00:27:13,959
Speaker 1: above it, and those mushroom cloud pictures are from that experiment.

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00:27:14,320 --> 00:27:16,560
Speaker 1: He said that the men were taken off their ships

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00:27:16,600 --> 00:27:19,199
Speaker 1: the bomb dropped, and then brought back to the ships

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00:27:19,240 --> 00:27:22,240
Speaker 1: to inspect their area. Obviously, this is a horrible idea

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00:27:22,760 --> 00:27:25,400
Speaker 1: and many of and he said many of his shipmates

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00:27:25,440 --> 00:27:27,959
Speaker 1: got cancer and he was lucky to be an electrician

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00:27:28,040 --> 00:27:30,160
Speaker 1: working at the bottom of the ship, so his area

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00:27:30,240 --> 00:27:33,520
Speaker 1: was spared. Most of the radiation servicemen who were a

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00:27:33,560 --> 00:27:36,919
Speaker 1: part of Operation Crossroads have nifty little cards proclaiming it,

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00:27:36,960 --> 00:27:39,480
Speaker 1: and he still has his card. I have no idea

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00:27:39,520 --> 00:27:42,199
Speaker 1: how to verify any of the story other than what

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00:27:42,320 --> 00:27:44,760
Speaker 1: little like ampus together online, So take the story as

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00:27:44,800 --> 00:27:47,480
Speaker 1: you would all remembrances of a ninety two year old man.

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00:27:48,320 --> 00:27:51,160
Speaker 1: But the pictures are still incredibly cool to have. Long

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00:27:51,240 --> 00:27:53,760
Speaker 1: story short, My family has these random pictures of a

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00:27:53,840 --> 00:27:56,280
Speaker 1: nuclear test, and I have no idea if they should

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00:27:56,320 --> 00:27:58,399
Speaker 1: go to into a museum or just stay in the family.

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00:27:58,440 --> 00:28:00,240
Speaker 1: But I have attached the pictures of the as I

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00:28:00,240 --> 00:28:03,439
Speaker 1: felt like fellow history lovers, you might enjoy looking at

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00:28:03,520 --> 00:28:06,800
Speaker 1: this yourself. I just asked that you don't share them

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00:28:06,800 --> 00:28:09,200
Speaker 1: without giving credit to my grandfather. Thanks for being so

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00:28:09,400 --> 00:28:11,240
Speaker 1: entertaining at work. My co workers and I love to

467
00:28:11,280 --> 00:28:14,080
Speaker 1: hear your science related episodes the most because we are

468
00:28:14,119 --> 00:28:19,560
Speaker 1: all analytical chemists and are complete nerds. Jessica Uh Jessica

469
00:28:19,600 --> 00:28:22,440
Speaker 1: says ps. The best slash worst pickup line my co

470
00:28:22,600 --> 00:28:25,280
Speaker 1: workers have ever made was after listening to the demon

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00:28:25,280 --> 00:28:28,119
Speaker 1: Cores episode. It goes, hey, person, you're so hot you

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00:28:28,119 --> 00:28:36,320
Speaker 1: make my Geiger Counter melt. Here's the thing. If you

473
00:28:36,400 --> 00:28:40,040
Speaker 1: say that to someone and they get it, laugh and

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00:28:40,080 --> 00:28:41,920
Speaker 1: then maybe want to go on a date with you,

475
00:28:41,920 --> 00:28:45,880
Speaker 1: you might have found your person. Yeah, I mean that's true.

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00:28:47,520 --> 00:28:49,720
Speaker 1: I just love this whole story of just like flipping

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00:28:49,760 --> 00:28:53,200
Speaker 1: through some family, you know, photos from back during their

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00:28:53,240 --> 00:28:55,960
Speaker 1: service days, all of a sudden, a mushroom cloud. What

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00:28:56,080 --> 00:29:00,000
Speaker 1: in the world. Thank you so so much, Jessica first

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00:29:00,000 --> 00:29:04,040
Speaker 1: into this email. The attached pictures were indeed very dramatic,

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00:29:04,080 --> 00:29:06,960
Speaker 1: and I would have found them quite startling if we're

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00:29:07,080 --> 00:29:11,640
Speaker 1: looking through them with my grandfather. Uh, if you would

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00:29:11,720 --> 00:29:13,600
Speaker 1: like to write to us about this or any other

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00:29:13,640 --> 00:29:16,200
Speaker 1: podcast or a history podcast that I heart radio dot

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00:29:16,280 --> 00:29:19,200
Speaker 1: com and then we are all over social media miss

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00:29:19,240 --> 00:29:21,719
Speaker 1: in History, which is where you'll find our Facebook, Twitter, Pinterest,

487
00:29:21,760 --> 00:29:24,640
Speaker 1: in Instagram, and you can subscribe to our show on

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00:29:24,680 --> 00:29:27,640
Speaker 1: Apple podcasts and the I heart Radio app and anywhere

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00:29:27,680 --> 00:29:35,040
Speaker 1: else that you get your podcasts. Stuff you missed in

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00:29:35,120 --> 00:29:37,880
Speaker 1: History Class is a production of I Heart Radio. For

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00:29:37,960 --> 00:29:40,640
Speaker 1: more podcasts from I heart Radio, visit the I heart

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00:29:40,720 --> 00:29:43,800
Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your

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Speaker 1: favorite shows,