Sunday, June 26, 2011

The o-yatoi who weighed the earth

A mid-Meiji encounter of science and religion at the summit of Mt Fuji

On a windy day in early August 1880, the priest called Kinoshita lost his sacerdotal cool. Half an hour ago, a balding foreigner had asked him, through an interpreter, if he could set up his infidel devices in Kinoshita's shrine - the Summit Sanctuary of the Sengen Goddess of Mt Fuji herself.

Unthinkable, fumed Kinoshita, as he sent the interlopers on their way. Yet now the interpreter, this gangling student-type, was coming over to pester him again. Would the estimable priest be so good as to reconsider his decision, the student was asking, because the American sensei wants to weigh the earth.

Thomas Corwin Mendenhall (left) did not come to Japan specifically to weigh the earth. As one of the 3,000 or so 'o-yatoi' or foreign employees of the Meiji government, he'd been invited to teach physics at the newly established Tokyo Imperial University. Arriving in Yokohama on September 21, 1878, he gave his first lecture the very next day, from a podium set up in a venerable Buddhist temple. (The images had been carefully moved aside for the occasion).

Mendenhall attached great weight to the experimental method. Experiments, you could say, were the making of him. Born in 1841, the youngest of five children, he was brought up on a farm in eastern Ohio. It was a young Quaker teacher, teaching through practical demonstration, who started him on the road to science. For instance, during recess, the girls' shawls were used to block out the windows. A pinhole in this screen produced a clear image of children playing outside, projected onto the room's white ceiling.

Money was scarce; the future physicist had to buy his copy of Euclid with a silver dollar he earned by driving a neighbour's cow twenty-five miles to market. The only way he could get a further education was to become a teacher, which he did by taking his teaching certificate at the age of sixteen. From his first job at a primary school, he worked his way up to a professorship at the new Ohio Agricultural and Mechanical College (now Ohio State University) in 1873. Then came the invitation to Japan.

Once in Tokyo, Mendenhall built, more or less from scratch, a modern physics laboratory, using equipment sent from friends in America; all his students would be required to do lab work. Some would also accompany him on field trips and take part in research projects.

It is unclear how Mendenhall lit on the idea of measuring the earth's gravity on the summit of Mt Fuji. Perhaps the idea came to him when the "most beautiful mountain in the world" had soared over the sea horizon, as if to welcome him, the day before his ship docked in Yokohama.

As for the apparatus, he'd become interested in measuring gravity by means of pendulums. A fellow o-yatoi, Professor Chaplin, the professor of civil engineering at Todai, lent him an astronomical transit instrument, by which the accuracy of the recording chronometers could be checked. Now all was set.

The scientists and their instruments travelled to the foot of Mt Fuji, by jinrikisha - the railway went only as far as Yokohama. The students had gone ahead to make arrangements. As the Americans arrived in Subashiri at night, it was not until next morning that the great volcanic peak revealed its full splendour. At which, Professor Chaplin turned to Mendenhall and exclaimed, "My God, I don't wonder they worship it."

At 8am, the party started its ascent. One of the "goriki" or porters had to carry the main part of the transit instrument, which weighed 160 pounds, but he still managed to outclimb the two scientists. By mid-afternoon, in the barren wastes of scoria above the treeline, they were struggling. And the summit still looked far away.

Just then, the Americans were overtaken by a band of pilgrims, all dressed in flowing robes of white, their leader urging them on with a small bell. Mendenhall noted that the leader limited each effort to one hundred steps, which he counted in a loud voice. After each advance, the pilgrims fell instantly to the ground, where they rested under their immense straw hats, until called to their feet again by the leader's bell.

PILGRIMS DESCENDING FUJI, a photo by Okinawa Soba on Flickr.

The pilgrims didn't seem to pay much attention to their leader's counting - instead, they timed their paces to their chanting of the mountain votary's prayer - "Rokkon, shōjō" (May our six senses be purified). The scientists fell in with this group, learned their chant, shared their climbing routine, and had their moral support through the rest of that day.

They put up for the night at a hut near the eighth station, where they admired the mountain's conical shadow as it stretched out further and further until the sun finally set. The pilgrims too stayed in this hut, yet all managed a comfortable night.

Next day, the scientists reached the summit. They soon found an adversary that they hadn't reckoned with - the strong wind that prevented them from putting up their tents. And even if somehow the tents could have stayed up, the blustering gusts would have disturbed the instruments too much for useful readings.

What to do? They peered down into the sheltered crater - perhaps three hundred feet deep, by Mendenhall's guess - but the difficulties of getting the instruments down its stone-raked walls looked insurmountable. It was then that they decided to ask the priest in charge of the summit shrine if they could use his main sanctuary as a temporary laboratory.

The scientists' first request was rebuffed - the priest seemed indignant even to be asked. Mendenhall decided to give him half an hour to recover his composure, then resolved to make another trial. This time the scientist explained, through one of the students, that his experiment was intended to compute the weight of the earth.

Signs of interest appeared on the priest's face and soon he agreed to lend his shrine to the scientists for three or four days. In a few hours all was ready: the image of Buddha was respectfully moved to the back of the hut, the pendulums were mounted on stones projecting from the walls, the chronograph was connected with the chronometer and set going, and the transit instrument was deployed near the door, ready to take star sightings.

Mendenhall's experiment drew on an illustrious heritage. It was Isaac Newton, no less, who was the first to hazard a guess at the earth's density. You'll find it in the Principia, Book III, The System of the World, Proposition 10, Theorem 10:

Accordingly, since the ordinary matter of our earth at its surface is about twice as heavy as water, and a little lower down, in mines, is found to be about three or four or even five times heavier than water, it is likely that the total amount of matter in the earth is about five to six times greater than it would be if the whole earth consisted of water, especially since it has already been shown above that the earth is about four times denser than Jupiter.

This was a prescient conjecture. But it still had to be verified in the hard currency of experimental results. The baton was taken up about half a century after Newton's death by Britain's Royal Society, which set up a so-called Committee of Attraction.

In 1774, this body sent Nevil Maskelyne, the Astronomer Royal, to visit a 3,500-foot mountain in Scotland. By measuring how far the mountain attracted a plumb line away from the vertical, the savants would be able to calculate by how much the earth's attraction outweighed, so to speak, that of the mountain.

Schiehallion, the mountain in question, was chosen for the Fuji-like regularity of its conical form. This, it was hoped, would simplify the task of estimating the mountain's density, on which the whole calculation depended. It may be that Schiehallion's form wasn't sufficiently Fuji-like; Maskelyne's result came in one-fifth too low, making the earth rather too light.

It fell to Henry Cavendish, another Committee of Attraction member, to perfect an indoors experiment. This would eliminate the geological guesswork, by measuring the gravitational pull of one lead sphere on another. The apparatus was so sensitive, indeed, that readings had to be taken through a telescope, from outside the sealed-off laboratory.

Published in 1798, Cavendish's paper puts the earth's density at 5.48 times that of water. It was Cavendish too who first wrote of "weighing the earth" - the earth's mass can, of course, be deduced from its density. In this way, he unwittingly coined the phrase that would later win over priest Kinoshita on the summit of Mt Fuji.

Twenty or so years later, another savant caught a slip in Cavendish's arithmetic - the actual result from his apparatus should have been 5.45. Nobody said that weighing the earth was going to be easy.

Mendenhall's experiment drew on work by later British and European scientists who used pendulums to take gravity readings both on the surface and at the bottom of deep mine-shafts. The idea was to find the difference between the two different gravity readings; the pendulum should swing slightly faster in the stronger gravitational field underground than it would on the surface.

Then, knowing the radius of the earth and knowing (or at least guessing) the density of the ground between the surface and the depths of the mine, you could educe the density of the whole earth. The method was pioneered by the British astronomer George Airy, not without tribulation. His first attempt, in 1826, failed after one of the pendulums met with an accident; a second try miscarried when the mine flooded.

The experiment was eventually completed in 1854, Airy's pendulum swinging just over two seconds per day faster below ground than above. After taking the advice of a mineralogist on the density of the overlying rock, Airy concluded that the earth weighed slightly more than six and half times heavier than the equivalent volume of water.

Mendenhall's innovation was to substitute a mountaintop for the mineshaft. Using self-devised pendulums for greater accuracy, he took readings first in Tokyo, then on Fuji, and then in Tokyo again. The mountaintop work was favoured by clear days and starry nights for the transit readings.

When the country below was covered in cloud, the scientists felt as if they were floating on an island in the sky. The pilgrims, apparently undisturbed, kept filing up to the shrine to make their obeisances and throw copper coins in at the door. One of the students collected up these offerings and took them to the priest.

When it came to estimating the volcano's density, Mendenhall went one better than Airy; he polled five different geologists and averaged their opinions. If Mt Fuji were 2.12 times denser than water - the mean estimate of the geologists - then the earth's density would be 5.51, Mendenhall calculated.

Announced the following year in a lecture "on pendulum experiments on the summit of Fujiyama", this result came within a hair of the currently accepted value.

SAILING INTO FUJI, a photo by Okinawa Soba on Flickr.

The following summer, the Mendenhalls sailed for home, catching a final glimpse of Mt Fuji from the ship's rail. Successful as the gravity experiments had been, the professor saw his students as his principal legacy. "Always fond of teaching," he wrote later, "I cannot but look back upon my three years with these well-mannered, good tempered, ambitious, and intellectually strong men as being ... the pleasantest and best of all my professional years."

The ambitious young men bore out their promise. One, Kikuchi Dairoku, went on to become a minister of education and, briefly, the first president of RIKEN, Japan's government-sponsored science research institute. Another, Tanakadate Aikitsu (standing, second from right in photo), made important discoveries in geophysics.

Quite probably it was Tanakadate (left), a north-country samurai, who handled the delicate negotiations with the priest of Mt Fuji's summit shrine. If so, he made a good impression. Just before the scientists left the mountaintop - a dense fog had rolled in, spoiling the view - Mendenhall sought out the priest who had made his experiment possible.

The professor wanted to express his gratitude with a generous sum of money but the priest refused all reward; it was an honour, he said, to have been able to help in the solution of such an interesting problem. Since then, wrote Mendenhall in his memoirs, "I have always taken much pleasure in naming this liberal-minded Japanese, named Kinoshita, who allowed me to transform a holy shrine of almost the oldest of religions into a laboratory of science and to substitute for his sacred images the most recent devices for the measurement of time."

Science and religion often came to blows in the second half of the nineteenth century. Yet, for a few days in August 1880 atop Mt Fuji, they achieved an amicable and productive cooperation.


Crew, Henry, Biographical memoir of Thomas Corwin Mendenhall, National Academy of Sciences, 1934

Dickey, John S, On the rocks: earth science for everyone, 1996.

Hughes, David W, The mean density of the earth, Journal of the British Astronomical Association, 1.2006 - and many thanks to Professor Hughes for kindly providing an explanation of how the Airy experiment worked.

Mendenhall, T C (Jr.) (1989) American Scientist in Early Meiji Japan: The Autobiographical Notes of Thomas C. Mendenhall

Mendenhall, T C, On pendulum experiments on the summit of Fujiyama for the purpose of ascertaining the force of gravity at that point, Abstract of lecture read October 20th, 1881

Tuesday, June 14, 2011

Manifesto of a solo mountaineer

In March 1933, a chance encounter in the snowbound Northern Alps prompted Japan's most famous "Alleingänger" to set down his philosophy in writing - and also, possibly, to start questioning it.

"You know, mate, you're living on borrowed time." Sitting in the mouth of a rocky bivouac cave, the leader of the climbing group doesn't mince his words. He's talking to a lone mountaineer outside in the snow, who, a few minutes ago, showed up from nowhere. Solo mountaineering doesn’t get a lot of support in early Shōwa Japan, not even among fellow alpinists.

The loner gives a slight nod but doesn't otherwise respond to the other's prophecy. He is, of course, Katō Buntarō, whose winter expeditions have attracted quite a bit of publicity. On one occasion, when he went missing for a day or two in the mountains, he's created newspaper headlines. And he was bringing another solo exploit to a close when he happened across Nakamura and his crew, up here in Yokoō-dani, and dropped in for a chat.

Until now, Katō hadn't felt the need to justify himself, but the bluntness of Nakamura’s address has struck home. Back in Kobe, he's prompted to write a kind of rationale. The resulting essay, On solo mountaineering (単独行について), is a glimpse into Katō's hard-driving spirit. It is a manifesto for solo mountaineering.

An "Alleingänger", says Katō, using the German word, is one who favours the avalanche- and stonefall-raked routes shunned by others, one who scorns to follow in the dust of another's trail, and boldly tackles one impossible line after another.

There's all the difference in the world between these solo alpinists and folk who just go hiking by themselves. Yet both types start out the same way; they are urged on by a love of nature and they have shy, self-willed personalities. That is, they are too shy to ask experts to take them climbing and too self-willed to burden themselves with companions who might slow them down.

This is not quite the full story, though. Soloing is more than just climbing without a companion: "If mountaineering is about gaining knowledge and hence solace from nature, then surely the most knowledge and the highest degree of solace is gained from solo mountaineering." If you have a partner with you, you sometimes forget to look at the mountains. But, when you climb alone, "no stick or stone can fail to captivate your heart".

Or perhaps it’s a contest with nature. If mountaineering is "doing battle with nature and prevailing, then surely the battle and the solace thereafter are that much more intense when you are alone, counting on nobody but yourself."

Soloing is not for everybody, Katō warns. Only mountaineers who actively want to solo are qualified to do so; to solo in a state of self-doubt is a crime. "If you solo because you know it's right for you, then you can make progress without agonising about it. If you're weak, you'll be tormented; crushed. The strong will grow stronger and flourish. So, soloists, be strong!"

We can be fairly certain that few or none of these arguments were rehearsed outside the bivouac cave on that March day in 1933; Katō was the taciturn type. Propped against the low-slung branch of a mountain birch tree, he kept his thoughts to himself. And Nakamura wouldn't have listened anyway: "There's no way I'd go into the mountains solo," he insisted.

But is it possible that Katō took Nakamura's advice to heart? When, three years later, he set off into a January snowstorm to traverse the north ridge of Yari, he was with a climbing partner. That was the last time anybody saw Katō and Yoshida alive; some time later, the bodies were found in the valley below, still roped together.

In his last year, Katō had changed his stance on solo mountaineering. With a partner, you could climb harder routes. And beyond the winter Japan Alps shimmered the eternal snows of the Himalaya …


Right now, Katō Buntarō is enjoying a renewed lease of fame. That is due to the manga Kokou no Hito (孤高の人) about “Mori Buntaro”, a character loosely based on the hero of Nitta Jirō’s novel of the same title. The novel, in turn, elaborates on the life of the real Kato Buntaro. The manga's popularity brings quite a bit of traffic to this blog – specifically to the post Life and death on Japan’s Matterhorn. What Katō himself had to say about solo mountaineering, you’ll find in the full text of his essay On solo mountaineering (単独行について).

Friday, June 10, 2011

Images and ink (8)

Image: Hodaka-dake in June by Ōshita Tōjiro (1870-1911)

Text: On Hodaka-dake, from Nihon Hyakumeizan (One Hundred Mountains of Japan) by Fukada Kyūya (1964):

As Kōda Rohan wrote: "Beyond the broad declivity in front of us rose up a noble and lofty range, manly in aspect, inspiring both awe and joy. Caught unawares, I was moved almost to tears. A reckless urge to reach out for the mountain took hold of me. For a moment, it was hard to say whether I held the mountain in my gaze or the mountain held me in his."

Related posts: Hodaka in winter and North ridge boogie

Friday, June 3, 2011

Journey to the centre of Mt Fuji

Discovering the crater in the company of a Heian-era literary scholar

The Warthogs came skimming up the slope, chasing their shadows over the snow. We leaned on our ice-axes, glad of an excuse to pause, and watched as the jets half-rolled into a ballistic arc over the mountaintop.

Craning upwards, the pilots must have seen Mt Fuji float, upside down, over their heads. It was clearly a good day for inspecting the crater. When we reached the summit shrine, all frosted up with rime-ice, I let slip my plan to Yamada-san. “Make it quick, then” he said. Our leader didn’t like solo excursions and November days are short.

A short distance under the radar station, I found what I was looking for – a ramp of snow that led smoothly down into the crater. No sign of ice or treacherous windslab. Cautiously at first, then with growing confidence in the Styrofoam snow that squeaked under my crampons, I made my descent.

The crater first floated into human ken during the ninth century. The earliest mention is in a Record of Mt Fuji (富士山記) by Miyako no Yoshika (834-879), an official at the Heian court and a scholar of classical literature. This is what he says:-

Mt Fuji takes its name from that of the district. Its deity is the Great God Asama. As for its height, it rises so far above the clouds that nobody knows how high it is.

The summit is flat and about a league across. It is sunken in the middle, in shape like a rice-steaming pot (koshiki). At the bottom of this pot, there is a mysterious lake and in the middle of the lake, a large rock. The rock is strangely shaped, just like a crouching tiger. Vapour rises incessantly from the crater. The lake’s colour is a pure and deep blue.

If one looks into the crater, it’s as if the water is seething. Looking at the mountain from afar, one often sees smoke and flames too. The summit pond is ringed with bamboo, which is a lush green and pliable. The snow never melts in spring or summer.

At the bottom of the ramp, I took stock. It was calm down here, sheltered from the gusts of snow blowing around the crater rim. There was no sign of a bamboo grove; just a sheet of rippled snow sloping down to a large black rock sitting at the crater’s lowest point.

If there was once a lake here, who came up to see it? According to Miyako no Yoshika, the mountain had only been climbed once, by En-no-gyōja. But this semi-legendary mystic and mage lived more than two centuries before Yoshika. In his own day, the chronicler says, “People can climb the mountain to its middle level, but it’s impossible to go further because of the ash which is always slipping downwards.”

Yet the Record of Mt Fuji has the ring of an eyewitness account. Crater lakes are found in many of Japan's volcanoes, though they tend to be short-lived. If anybody did go up Mt Fuji in Yoshika’s lifetime, he first had to brave the bear-haunted and trackless forests. Above the trees, tumbling rocks and slip-sliding ash would await him, the unsteady ground steaming with fumaroles and racked by earth-tremors.

The attempt would have been hazardous. Around the turn of the ninth century, something prodded the Great God Asama into a renewed frenzy. Bursting from the summit region in 800-802, the ash clouds of the Enryaku eruption turned day into night. Debris raked the seaward slopes, cutting the main highway to the eastern provinces.

A smaller eruption in 826 was merely a prelude to the great Jōgan event. In 864-865, red-hot lava flows torched the forests on Fuji’s northern flanks before rolling down into Se-no-umi, broiling its fish and cutting the lake in two.

Faced with this onslaught, the authorities offered the Great God Asama a more commodious shrine (in what is now Fujinomiya). This may have been early in the ninth century. Then, in 859, they promoted him to the senior grade of the third court rank. And when that didn’t placate him, they censured the governor of Kai for neglecting the proper rituals and demanded an apology on the god’s behalf.

In hindsight, the officials might have claimed a partial success. Although Mt Fuji rumbled on for another two hundred years, it never again erupted on the same scale. And, soon after the Jōgan eruption, it showed quite another side to its personality, as Miyako no Yoshika records:-

On November 5th, in the 17th year of Jōgan (876), the officials and people were celebrating a festival in accordance with an ancient rite when, as the day wore on towards noon, the sky cleared wonderfully. Looking up towards the mountain, they saw how two beautiful maidens robed in white danced above the summit, seemingly a span or more above it. Several local people witnessed this; a very old man passed on the tale.

Today, it was snow-devils that the wind was chasing around the crater rim. The winter sunlight set the ochres and terracotta of the rock walls aglow, as if freshly scorched by the volcano’s fires. It was hard to believe, as the savants insist, that Fuji’s central crater fell silent more than two thousand years ago. All the recent outbursts have issued from vents on the sides of the mountain, including those big eruptions in Yoshika’s day. Indeed, a flank eruption is chronicled in his Record of Mt Fuji:

At the eastern foot of Mt Fuji is a small mountain, which the local people call the new mountain. Originally this was flat ground, but in March of the 21st year of Enryaku (803) black smoke and steam came churning up and, after ten days, the new mountain was formed. Probably a god created it.

Up on the crater rim, Yamada-san would now be examining his altimeter watch. Feeling like an Apollo astronaut on the last moon mission – too much to see in too little time – I moved over to the black rock. Its anthracite facets were so dark, amid the snow-glare, that they seemed to suck the noonday light into themselves. What was this stuff…?

Pottering about in this crater a century ago, the mountaineering missionary Walter Weston had to ask himself a similar question:-

On the flat bottom we found great masses of newly fallen rock, and in a crevice of one of these a curious white substance embedded. Our friend described this as a great marvel – nothing less, indeed, than “petrified snow!” Possibly it was really some sort of gypsum, or even chloride of ammonia, which is sometimes found in the cooler part of volcanic fissures and fumaroles.

Perhaps Fuji does from time to time put out a crystal or two, together with its effusions of ash and lava. That would make sense of another enigmatic passage in Miyako no Yoshika’s account:

This must be a place where hermits and wizards disport themselves. As I’ve heard, during the Shōwa era (834-848), pearls and jewels rolled down from the mountain, each jewel with a little hole through it. These were probably beautiful gems that once adorned the reed screen of a hermit’s cell.

On the crater floor, I looked round for a souvenir – a beautiful gem would do nicely – but the ground was metres deep in snow. No matter, now it really was time to go.


A tentative translation from modern Japanese of the full text of Fujisan-ki. The chronicle was originally written in kanbun. It first appears in the Honchō-monzui, an anthology compiled in the mid-11th century.

Fujisan to Nihonjin, edited by Seikyūsha editors, Seikyūsha 2002

Mt. Fuji: The Wellspring of Our Faith and Arts, Shogakukan, 2009.

Playground of the Far East, by Walter Weston (1918)

Aerial picture of summit by courtesy of JTB; Miyako no Yoshika and Warthog from Wikipedia; detail of flying apsara courtesy of 日本の美をめぐる, No. 11.

Wednesday, June 1, 2011

Images and ink (7)

Image: Morning over Tsurugi-san, woodprint by Yoshida Hiroshi (1926)

Text: On Tsurugi-dake, from Nihon Hyakumeizan (One Hundred Mountains of Japan) by Fukada Kyūya (1964):

Yes, as its name suggests, Tsurugi has all the sharpness and rigour of a sword. ... Defended by its iron citadels and snowy moats, the summit was long held to be inaccessible. According to legend, this was the mountain where Kōbō Daishi wore out a thousand pairs of straw sandals in vain attempts to scale it...

Related posts: The tiltyard of alpinism and Tales of the Genjiro