American Science and the Solar Eclipse of 1878


mic Listen to the podcast:

Journalist David Baron discusses his book about the furor surrounding the total solar eclipse of 1878.

americaneclipsecoverMany Americans will be treated to a rare total solar eclipse on August 21, when the shadow of the moon crosses in front of the sun in a path from Oregon to South Carolina. The eclipse, which will occur in the late morning on the West Coast, is expected to produce a 70-mile-wide band of darkness that will be seen by tens of millions of people. The same event happened back in 1878, and it was an important occurrence for three scientists who wanted to learn more. Journalist David Baron chronicles that story in his book, American Eclipse: A Nation’s Epic Race to Catch the Shadow of the Moon and Win the Glory of the World. Baron visited the Knowledge@Wharton show on SiriusXM channel 111 to shed some light on those notable scientists.

An edited transcript of the conversation follows.

Knowledge@Wharton: You profiled Thomas Edison, James Craig Watson, who was a planet hunter, and astronomer Maria Mitchell. Why these three?

David Baron: The eclipse of 1878, which passed over America’s Wild West from Montana Territory down to Texas, attracted dozens of the era’s great scientists out to that part of the country to study the sun and solar system. I chose those three characters because they all had something really on the line and something to prove.

Thomas Edison was out to show that he was a scientist, not just an inventor. James Craig Watson, from the University of Michigan, was out to find a planet called Vulcan. And Maria Mitchell from Vassar, who was a rare female scientist and by far the most famous one in the United States, was out to show the American public that women could be scientists.

Knowledge@Wharton: This solar eclipse was in advance of Edison inventing the light bulb. Did this help him down that path?

Baron: Yes, it’s a fascinating time in the life of Thomas Edison. He went west in 1878 for this total solar eclipse, right after he had become a global celebrity because of his invention of the phonograph. The very day after he returned from Wyoming, he started work on the light bulb. There are some subtle ways in which his eclipse expedition helped him with the light bulb, most importantly because of what he learned about public relations, which was key to his ability to raise money and keep the press on his side while he worked and worked and worked to perfect the light bulb.

Edison was a natural with PR, but in the summer of 1878, he just had the newspapers wrapped around his finger. He headed west for the eclipse. He came up with a device called the tasimeter, which was going to be “bigger than the phonograph,” as the newspapers said. It was a very sensitive heat detector that he was going to use to study the eclipsed sun. He had the newspapers writing glowing reports about the tasimeter even before he had ever created it. That’s the same thing he did with the light bulb. He claimed that he had solved the problem of incandescent lighting long before he really had, but he kept the press on his side until he actually did solve the problem.

Knowledge@Wharton: Maria Mitchell was trying to prove that women could be very successful business people and scientists. The timing was interesting because it was still 40 years or so away from women’s right to vote.

Baron: Yes, and the 1870s was a time when higher education for women was just getting off the ground. Vassar College had been founded in the 1860s, then Wellesley and others were coming along. But that was a time when educating women in college was considered a dangerous experiment.

“I chose those three characters because they all had something really on the line and something to prove.”

There was a book that came out in 1873 by a Harvard doctor who claimed that higher education could ruin a girl’s health, that if a young woman used her brain too much, it sapped energy from her maturing reproductive organs and would turn her into a sterile, masculine invalid. This was taken seriously. In 1878, Maria Mitchell, who thought this was ridiculous, put together an all-female expedition of scientists to Denver, Colorado. It was kind of a political theater to show the American public that this book was crazy and that women could be educated, smart, scientifically minded and healthy.

Knowledge@Wharton: Tell us more about James Craig Watson.

Baron: Long before the planet Vulcan showed up on Star Trek, it was thought to be a real planet back in the 1800s. It was thought to orbit the sun between Mercury and the sun. If you look at some solar system diagrams from that period, the planets go Vulcan, Mercury, Venus, Earth. The reason astronomers thought Vulcan existed was because Mercury’s orbit didn’t quite make sense, based on Newtonian mechanics. It acted as if there was something tugging on it, so astronomers guessed that there must be a planet between Mercury and the sun. They called it Vulcan. No one had ever reliably seen it, but they thought orbited so close to the sun that it would never be in the sky at night, and you couldn’t see it in the daytime because it would be lost in the sun’s glare.

However, during a total eclipse, when the moon blocks the bright surface of the sun, enabling you to look right around the sun, you might be able to catch a glimpse of Vulcan. James Craig Watson, who had made a reputation for himself by finding asteroids, was determined to find Vulcan during the eclipse of 1878.

Knowledge@Wharton: How long in advance was it known that this solar eclipse was actually going to occur?

Baron: It was known decades beforehand, probably even a century beforehand. By the 1800s, astronomers knew how to predict eclipses with great accuracy. They might not be able to map the path of the total eclipse down to a couple of miles until maybe a few years beforehand, but they knew the eclipse was coming long in advance.

Knowledge@Wharton: We mention what happened with Thomas Edison. What happened with Watson and Mitchell post-eclipse?

Baron: During the eclipse, James Craig Watson convinced himself that he actually found the planet Vulcan. That was the big headline to come out of the eclipse of 1878. In fact, Americans were very proud that one of their own, an American astronomer, had found this planet that astronomers had been looking for for so long.

“There were Europeans who thought that the United States would never compete in any significant way when it came to science.”

Of course, we know today that Watson was wrong. There is no planet Vulcan, but that was not immediately evident. Within a year after the eclipse, other scientists were starting to question if maybe he was wrong. He had quite the ego, however. James Craig Watson could never accept there was any chance that he had been wrong. And he came up with a crazy scheme to find Vulcan without an eclipse. He was going to build a special telescope to find it. He quite literally worked himself to death two years after the eclipse trying to find Vulcan. It was his ultimate downfall.

As for Maria Mitchell, she went on and continued to push for women’s higher education and women in science. She was getting on in years, however. This was sort of the very end of her career, but she left her mark. A whole generation of female scientists came along after her — those who were educated by her, and those who were educated by her former students. She really left her mark on opening the doors to science for women.

Knowledge@Wharton: This was an important time for scientists in the United States, correct?

Baron: Absolutely. That’s one of the reasons I call my book American Eclipse. It wasn’t just because the eclipse took place in the United States, but because America really embraced this eclipse as its chance to show the world what we could do in science.

By 1878, the United States had definitely emerged on the global stage as an industrial power. We were being taken very seriously economically. But intellectually, Europe looked down on us. Europe was where most of the world’s respectable literature and art and music and architecture came from, and Europe was the center of science. There were Europeans who thought that the United States would never compete in any significant way when it came to science.

But there was a small band of American astronomers and other scientists who were determined to show Europe that we could compete. The eclipse of 1878 became a chance for the American public to rally around the scientists and to decide that we did want to compete in that realm. By the turn of the century, the United States really was a peer with Europe when it came to science. By the early 20th century, we had become the world’s leader.

Knowledge@Wharton: When you think about the eclipse itself, it’s not a long event. But getting the information and gathering it and taking it forward is really the groundbreaking part.

Baron: That’s the thing about a total solar eclipse. I am an eclipse-chaser myself. I’ve seen five solar eclipses. They are exceedingly brief. They usually last just two or three minutes, but they are just absolutely awe-inspiring. So here I was writing a book about an event that lasted three minutes in 1878, but that was a really important three minutes. Astronomers planned for literally years, put together their expeditions over the course of months, traveled for days or weeks to get out to the West, and it all came down to three minutes of observation.

Knowledge@Wharton: Let’s talk about what’s going to happen with the eclipse on August 21.

Baron: Solar eclipses are not that rare, but total solar eclipses are very rare for any given point on Earth. This will be the first time in 38 years that a total solar eclipse has been visible from anywhere in the 48 lower United States. And it will be the first time in 99 years that total solar eclipse will cross the country coast to coast.

First of all, everyone in North America will see at least a partial eclipse on August 21, so it is an event that everyone will be involved in and, we should say, find a way to observe safely without damaging their eyes.

For those in what’s called “the path of totality,” which is 70 miles wide and goes from Oregon to South Carolina, for up to two minutes 40 seconds, the eclipse will be total. A total solar eclipse is a fundamentally different experience from a partial eclipse. During the total eclipse, it will go dark in the middle of the day. Bright stars and planets will come out, and during the total eclipse it actually is safe to look at the sun with the naked eye. You will see a sun like none you’ve seen before. It’s just the most glorious sight in the heavens. You’ll see the sun’s outer atmosphere, which is called the solar corona, its crown. And that’s what it looks like, a shimmering golden crown in the heavens.

The partial eclipse will last for several hours, depending on where you are. You’ll want to observe it safely. The best way to do it is to get yourself a pair of eclipse glasses. They don’t have to be very expensive. With them, you can actually look at the sun safely and see the sun turn into a crescent, and then become its normal sun again.

Knowledge@Wharton: Where will you be?

Baron: I will be in Jackson, Wyoming, which is in the path of totality. In Jackson, at about 11:35 a.m. the sun will completely go away, and we’ll be able to look up in the sky and see the planets and stars.

“A total solar eclipse is a fundamentally different experience from a partial eclipse.”

Knowledge@Wharton: In 1878, was there was a bit of a feeding frenzy in the scientific community because of this event?

Baron: Yes. Again, because a total eclipse was very rare for any given point on Earth. A total eclipse will occur somewhere on Earth about once every 18 months, but only in a very small area and often very hard to get to. Back in that era, scientists would send these expeditions off to wherever the total eclipse was going to be — India or North Africa or Siberia. But it was pretty rare to have one in our own backyard. So even though it was only three minutes, it was a feeding frenzy. It was an opportunity no one wanted to miss out on.

Knowledge@Wharton: The sense I got with Maria Mitchell is that her goal wasn’t necessarily the learning off of the eclipse itself. It was a proving ground for women and for what they could do.

Baron: Absolutely, yes. She was really trying to change people’s minds, more than trying to discover something in the sun or solar system. But then you could say the same about Edison. He was trying to conduct a study of the sun, but everything he did was involved with public relations. This was an opportunity to bolster his reputation not only as an inventor, but as a scientist, as someone to be taken seriously beyond just tinkering in the laboratory.

Knowledge@Wharton: What happened in Texas with the eclipse?

Baron: I mostly in my book focus on what happened in Colorado and Wyoming, where people knew the eclipse was coming and were excited about it. However, I do open my book with quite a dramatic story of what happened in Texas, where a lot of people didn’t know it was coming. They were out in their farm fields in the middle of the afternoon and looked up in the sky, and suddenly the sun was gone. It had been replaced by this shimmering crown in the heavens. They were, understandably, absolutely terrified. Many were convinced it was Judgment Day and this was Christ returning. One father, unfortunately, took it very seriously and decided he was not going to stick around for the apocalypse and decided he was going to go to the other side as quickly as possible and take his son with him. He killed his son with an ax, and then he took a razor to his own throat. This was not ancient times. In 1878, people were still terrified by eclipses. At least some were.

Knowledge@Wharton: How much do you think we can learn from eclipses these days?

Baron: A lot of science will be going on during the August 21 eclipse. There are still studies to be done of the solar corona that can be done best during a total eclipse. There are going to be some citizen science experiments where members of the general public are being asked to take pictures and videos. There’s one called the Eclipse Megamovie Project, where you sign up and download an app onto your smartphone. If you’re in the path of totality and take pictures or videos with your smartphone, those will be uploaded and combined into a continuous movie of the eclipse that will be constructed to see what the solar corona did during the hour and a half that it will take for the moon’s shadow to move from Oregon to South Carolina.

Citing Knowledge@Wharton


For Personal use:

Please use the following citations to quote for personal use:


"American Science and the Solar Eclipse of 1878." Knowledge@Wharton. The Wharton School, University of Pennsylvania, 14 August, 2017. Web. 19 September, 2017 <>


American Science and the Solar Eclipse of 1878. Knowledge@Wharton (2017, August 14). Retrieved from


"American Science and the Solar Eclipse of 1878" Knowledge@Wharton, August 14, 2017,
accessed September 19, 2017.

For Educational/Business use:

Please contact us for repurposing articles, podcasts, or videos using our content licensing contact form.