The first to receive firm news of the appearance of some faraway Krakatoa-induced waves was Charles Darwin's son George, shortly after he was elected (by the narrowest of votes) the professor of astronomy at Cambridge. * His friend Major A. W. Baird, who had the post of chief of the Tidal Survey of India, wrote to him in Cambridge to say that ‘the wave caused by the volcanic eruption at Java is distinctly traceable on all the tidal diagrams hitherto received, and I am informed of a great tidal disturbance at Aden on August 27; but the daily reports are always meagre in information. Kurrachee and Bombay also show the disturbance, and as far as I have examined the wave reached halfway up to Calcutta on the Hooghly.'
This last – the news that waters had rushed up the Hooghly River almost to the city that was then the capital of British India – did it. The Royal Society promptly asked for an immediate report. Major Baird swiftly obliged with a six-page summary of his Survey stations' reports from across that immense swathe of imperial territory that stretched between Aden and Rangoon. And the Krakatoa Committee, recognizing a significance that went beyond the simple threat to Calcutta, immediately commissioned a senior Royal Navy captain to investigate the phenomenon, worldwide.
Records from tide-gauges at ports all across the world were speedily gathered in. An early analysis showed a fascinating, but not entirely unanticipated, trend: almost all of the stations that recorded sudden and unexpected waves that could be positively linked to the eruption (by their timing and their type) lay to the west and south of the island.
Almost all: not Batavia herself, which lies eighty-three miles away to the east as the crow fines, and considerably further so far as a tidal wave might pass. Despite where she lay, the capital city did indeed witness what even the Royal Society saw fit to call ‘a wall of water’, when the wave hit her gauge at 12.36 p.m. on the Monday afternoon – two hours and thirty-four minutes after the explosion. According to the Reverend Neale, the water rushed into the Batavian canal system, rising suddenly by several feet, forcing hundreds of merchants and residents to flee for their lives.
The day – unusually cold, half dark and drab, the air still filled with grey, gritty ash that got in the hair and the eyes and the teeth – had begun, surprisingly, with a fair sense of stoic normality. The steam-trams were filled with people setting off for work, the markets were thronged, the private horse-drawn carriages were trotting around the Koningsplein, their occupants talking excitedly about the events of the night before, confident that the worst was over. Then came the arrival of what was swiftly understood to be the huge relic of the great tsunami – the remains of a wave that somewhere had been much, much worse – and it made all these good burghers of Batavia realize, very suddenly, that in fact the worst was still to come.
The maximum height of this bore (the needle on the Batavia tide-meter shot up vertically, clear off the scale) was at least seven feet and six inches – a fraction of the height of the devastating waves that destroyed Anjer and Telok Betong maybe, but an impressive enough display. The waters promptly fell back again, to ten feet below normal sea-level, and then rose back up again, then sloshed back down – oscillating a total of fourteen times over the next twenty-eight and a half hours, the height of the successive waves diminishing all the while. Finally, after what was no more than a three-inch ripple hit the Batavia tide-meter at 5.05 on the afternoon of the next day, the Tuesday, they vanished clear away.
But Batavia alone in the area experienced the great wave. Almost no other places to the north and east of the volcano experienced anything at all – Singapore's tide-meters registered nothing, nor was there any discernible blip in the records of Hong Kong, Yokohama or Shanghai; and even at Surabaya, at the eastern end of Java, the disturbance that was picked up on the port's three tide-gauges was only ten inches, ‘too insignificant to be otherwise noticed’. There is a very simple reason for the lack of any dramatic effects on this side of the volcano, as a glance at the map will show.
To the east of Krakatoa the two sides of the Sunda Strait pinch inwards like the jaws of a nutcracker. There are islands blocking the way too – Thwart-the-Way Island being one such, notorious in its nuisance value – and before a wave has any chance of touching Batavia port herself it reaches long fingers of shallows and sandbanks and further inlets and reefs, all of them conspiring to slow down and frustrate the eastward movement of any wave. Nothing would stand in the way of a sound wave or a shock wave; but, faced with the dissipating influence of the shoals and headlands, a water wave would essentially not move eastwards at all, as the recorders everywhere confirm.
However, to the west of Krakatoa, barring the presence of a small headland called Vlakke Hoek in southern Sumatra that acts as a small chicane on a westbound wave's right-hand side, there is only the wide-open sea of the Indian Ocean. Any tsunami moving out from the eruption in this direction would be free to go wheresoever it wished, without maritime hindrance or interruption. And in August 1883 the great ten o'clock wave did indeed fan out westward entirely untrammelled, and managed to go just about anywhere and everywhere it wanted. Two types of wave were detected: what were called long waves, which reverberated back and forth at periods of as much as two hours; and the short waves, which were steeper and with a much less regular and more frequent repeat.
The old Dutch port of Galle, close to the southern tip of the island of Ceylon, is where the arrival of these short waves – or more precisely, a sequence of fourteen waves, each separated by just a few minutes – was first noticed. The Ceylon Observer correspondent filed on 27 August that
... an extraordinary occurrence was witnessed at the wharf at about 1.30 p.m. today. The sea receded as far as the landing stage on the jetty. The boats and canoes moored along the shore were left high and dry for about three minutes. A great number of prawns and fishes were taken up by the coolies and stragglers about the place before the water returned.
A woman was killed at the port of Panama – still in Ceylon, not on the isthmus – when she was swept from the harbour bar by an immense influx of water. Both the Panama harbour-master and the local ruler, the splendidly titled Ratamahatmaya, said later that ships had suddenly sunk downwards and were then drawn backwards to be left stuck in the drying mud, their anchors exposed – and just as suddenly were borne up by an inrushing surge of water. The local streams, with hitherto sweet water, all promptly turned salty for at least a mile and a half upriver. The woman who died, from the injuries she sustained in falling while she was carrying a sheaf of paddy from the fields, is thought to have been the most distant casualty of the eruption that took place nearly 2,000 miles away.
At Hambantota, further south still, Ceylon government officials estimated the height of the wave to be twelve feet, and said that, like at Panama, its currents were irresistible, taking small craft back out to sea, and then sweeping them back and dashing them to pieces on shore. But however violent, there were no casualties here; nor were there any further afield.
The long waves tended to be the ones that were recorded by the
Tiny oscillations in the tides were noticed nearly 11,000 miles away from Krakatoa, such as here at Socoa, a small port near the French resort of Biarritz.
automatic tide-gauges around the world, and it is these that make up the bulk of the formal record; the short waves tended to be more the stuff of anecdote, and, because they oscillated so swiftly, rarely made an appearance on the recorders. By the time the long waves reached India they were diminishing, fast – fourteen inches high in Madras, a series of ten or so six-inchers at Calcutta, a foot high in Karachi, half that in Aden. They spread south-westwards towards the African coast as well: they broke a hawser of a boat moored in Port Louis, Mauritius; and in the rarely visited Indian Ocean reef harbour known as Cargados Carajos the captain of the Evelina reported huge, smooth oscillations in the sea, breaking only when they came into contact with coral heads. Already the wave was 2,662 miles from its point of origin, and racing steadily along at a calculated 370 miles each hou
r.
A four-foot-high wave was noticed at Port Elizabeth, on the bleak and generally unlit east coast of South Africa, * and undulations were picked up at Cape Town. A visiting German South Polar expedition (which failed to reach its goal) on the island of South Georgia saw the icebergs and brash in the harbour of the whaling station at Grytviken lifted fifteen inches in a series of a dozen recorded and remarkable swells.
And so the waters progressed ever outwards – with numerous waves of different types and styles, heights and frequencies, and deriving from what oceanographers now reckon were a number of different causes too. Eventually they ran out of steam and reached as far as they could go, in the further recesses of northwestern Europe. By the time they reached the North Atlantic, and then the Bay of Biscay, the oscillations were small indeed – such that the tide-diagrams had to be photographed and blown up in order to be able to measure the fluctuations in the record.
But they are there all right, tiny but still distinct. In Socoa, a tiny French harbour near the more celebrated resort of Biarritz, and 10,729 sea-miles from Krakatoa, there were seven undulations, each of them three inches high – barely enough to be noticed by promenaders on the beach, though I like to fancy pomaded young men and their lady friends skipping amusingly out of the way when the unusual small swells suddenly threatened their boots and their turn-ups. Further north at Rochefort, a town on the Charente a little north of the Gironde and Bordeaux, the magnifying power of the estuary pushed the waves up to five inches high – they had sped there from the volcano at a calculated (and now slightly faster) rate of 414 miles per hour, barely slowing as they did so.
And finally, turning the corner into the English Channel, the slightest trace only is noticeable. There is a ripple recorded at Cherbourg, another at Le Havre and an irregular but discernible series of undulations at Devonport, close to where all Royal Navy cadets are now trained to be officers. But closer in – at Portland, Plymouth and Dover, nothing. Maybe there is just the vaguest sign of it on the gauge on the inner side of the Portland breakwater – though the Royal Society report admits, ‘the indications of disturbance are not very conclusive, as no regularity of period is traceable in the small indentations which do appear’.
I confess I would have derived no small pleasure from discovering that on the Tuesday morning, when waves were seen in France and in the West Country, the tide-gauge in Dover port also suddenly startled its keeper, with a splash, or a slop, or a curious and inexplicable swell. But there was to be no such luck. With Dover being no less than 11,800 sea-miles from the Sunda Strait, and lying at the distant end of a channel in which the water shallows to a few hundred feet and less, which would kill or dampen the kind of long waves that were produced by the eruption, it is perhaps not surprising to learn that the gauges here showed no deflection at all. The air wave may have found its way to Greenwich, seven times; but the sea-wave was brought up short, 500 miles from home, and never arrived near the British capital, even once.
Yet other, quite different effects of the eruption were before long visible in London, New York and other northern capitals, and many of them were aesthetically and dramatically quite memorable. Art was born out of the after-effects of this volcano – art that was then quite unexpected. Though not so popular today, it is not entirely forgotten. For the millions of tons of dust that were hurled into the upper air in the East Indies disseminated themselves around the world for many years and caused all manner of extraordinary phenomena – not the least of which were sunsets. These were seen all over the world decked out in the most lurid rainbow of colours, and they attracted the interest of a great number of suddenly excited painters. *
One of the more prominent of these was Frederic Edwin Church, a member of what came to be known as the Hudson River School of American nineteenth-century landscape painters. He turned out to be precisely the kind of artist who would benefit from the atmospheric consequences of Krakatoa.
Frederic Church specialized in highly dramatic landscapes and highly coloured skyscapes – he had a predilection for the grand (his gigantic Niagara presents an astonishing image of the raw power of falling water) and the excessively radiant (his Twilight in the Wilderness has an unforgettable richness about its evening colour). Both of these artistic preferences came together in December 1883 when Church – supposedly well aware of the remarkable effects of Krakatoa's spreading trail of dust on the world's sunsets – travelled north from his ornate Moorish castle in the riverside town of Hudson, to the very tip of upstate New York, on the Canadian border. There he would try to capture an image of what he suspected would be an especially livid northern twilight.
He chose Chaumont Bay, at the very eastern end of Lake Ontario. The early-winter ice would be piling up in the westerly winds; there would be newly undraped trees on the wispy peninsulas; and above all there would be the vast expanse of the lake into which the setting sun would appear to sink. He chose to render the image in watercolour. The resulting picture – not surprisingly called Sunset over the Ice on Chaumont Bay, Lake Ontario – has a range of colours in the sky, a gently intermingling play of pinks and mauves and orange and salmon and purple that is quite astonishing, and unusual, and suggestive of something happening, something inexplicable, high in the evening atmosphere. It is the only major painting to be created in the immediate aftermath of Krakatoa: and even if Church had not set out with the deliberate intention of making post-eruptive art, the piece stands now as vivid documentary testimony to the giant volcano's effects. *
Lesser artists had a field-day. The most notable was William Ascroft, who lived beside the River Thames in Chelsea. Early in September, two weeks after the eruption, he noticed that London was suddenly being gifted with a series of memorable setting suns and, more interesting, unusually strong afterglows. He painted them at a furious rate – creating a total of no fewer than 533 watercolours over the months of his fascination.
On especially gorgeous evenings he might make several paintings, one every few minutes, creating as he did so a kind of time-lapse image of the entire process. On 26 November, for example, he painted the aftermath of the sun's disappearance once every ten minutes between 4.10 p.m. and 5.15 p.m., catching a sequence of fiery purples and oranges with all the fleet-footed accuracy of a film camera. He wrote lengthy notes and analyses of what he saw – ‘Blood Afterglows' and ‘Amber Afterglows’ among them – and examples of the beaming coronas that often surrounded the setting sun itself and which were named, after the Hawaiian naturalist * who first spotted them, ‘Bishop's Rings’. All 500 of his paintings later went on show at an exhibition in a museum in South Kensington. They remain today inside what is now the Natural History Museum, locked away and half forgotten.
Dust of all grades and compositions was thrown into the air by the eruption. Much of it, too heavy to be kept on high for long, fell down as drifting veils of grey, and was widely reported as having done so. Ships at sea experienced dust falls for a fortnight after the eruption: the Brani and the British Empire came under a slow rain of a white ash that one master said ‘looked like Portland cement’, when they were sailing in the Indian Ocean within a 2,000-mile range of the volcano; the Scotia experienced falling dust until 8 September, when she was off the Horn of Africa, 3,700 miles away.
But the lighter material, the finest particles of all, were thrown up right through the troposphere until, almost defying the pull of gravity, they were caught up for months in the lower reaches of the stratosphere † itself. Modern estimates suggest the Krakatoa eruption hurled material at least 120,000 feet into the air – some say 160,000 feet, or thirty miles. Tests have since shown that up so high, material can hover in a kind of weightless stasis.
A dust particle with a diameter of a micron – whether it is an aerosol droplet or a tiny fragment of volcanic silicate mineral makes no difference – has recently been shown to take many weeks to descend vertically through just half a mile of stratosphere. A particle of half a micron in diameter will take many months
to fall, so slight is the tug of gravity upon it. Yet horizontal movement was apparently no problem for the Krakatoa material. The strong globe-encircling winds spread them far and wide. And the rains that would tend to flush out those particles that might have been tempted to stay in the lower reaches were of course non-existent up high.
And so they stayed, undisturbed, for very long periods. And by refracting and filtering and in a myriad other ways altering so vividly the colours of the sunlight that passed by them, and by staining the crepuscular skies with vermilions and passion-fruits and carmines and royal mauves, so they ensured more potently than any other effect that Krakatoa would soon become the most famous volcano in world history.
Krakatoa killed more people than any other eruption, and for that it remains notorious: but it became much more widely known to hundreds of millions of people around the world for a more benign and beautiful reason, one that all could readily see for themselves each time they looked westwards at eventide.
The poets were inspired in much the same way as the painters. Tennyson is widely believed to have been thinking of Krakatoa when in his almost wholly forgotten epic poem St Telemachus, published nine years after the eruption, he wondered out loud:
Had the fierce ashes of some fiery peak
Been hurl'd so high they ranged about the globe?
For day by day, thro' many a blood-red eve,…
The wrathful sunset glared…
The Royal Society's Krakatoa Committee, displaying the almost obsessive need for the complete and the comprehensive that was so much a signature of Victorian studies like this, invited responses from the general public. They received wagon-loads of material, * and painstakingly catalogued every single report of every atmospheric phenomenon, no matter how trivial, of which they were made aware. Two thirds of the Society's eventual 494-page report is devoted to ‘the unusual optical phenomena of the atmosphere, 1883–1886, including twilight effects, coronal appearances, sky haze, coloured suns, moons &c’.