The Island of the Colorblind

Knut was fascinated not only by the pigs but by the richness of the vegetation, which he saw quite clearly, perhaps more clearly than the rest of us. For us, as color-normals, it was at first just a confusion of greens, whereas to Knut it was a polyphony of brightnesses, tonalities, shapes, and textures, easily identified and distinguished from each other. He mentioned this to James, who said it was the same for him, for all the achro-matopes on the island – none of them had any difficulty distinguishing the plants on the island. He thought they were helped in this, perhaps, by the basically monochrome nature of the landscape: there were a few red flowers and fruits on the island, and these, it was true, they might miss in certain lighting situations – but virtually all else was green.[12]

‘But what about bananas, let’s say – can you distinguish the yellow from the green ones?’ Bob asked.

‘Not always,’ James replied. ‘Tale green’ may look the same to me as ‘yellow.’’

‘How can you tell when a banana is ripe, then?’

James’ answer was to go to a banana tree, and to come back with a carefully selected, bright green banana for Bob.

Bob peeled it; it peeled easily, to his surprise. He took a small bite of it, gingerly; then devoured the rest.

‘You see,’ said James, ‘we don’t just go by color. We look, we feel, we smell, we know  – we take everything into consideration, and you just take color!’

I had seen the general shape of Pingelap from the air – three islets forming a broken ring around a central lagoon perhaps a mile and a half in diameter; now, walking on a narrow strip of land, with the crashing surf to one side and the tranquil lagoon only a few hundred yards to the other, I was reminded of the absolute awe which seized the early explorers who had first come upon these alien land forms, so utterly unlike anything in their experience. ‘It is a marvel,’ wrote Pyrard de Laval in 1605, ‘to see each of these atolls, surrounded by a great bank of stone involving no human artifice at all.’

Cook, sailing the Pacific, was intrigued by these low atolls, and could already, in 1777, speak of the puzzlement and controversy surrounding them:

Some will have it they are the remains of large islands, that in remote times were joined and formed one continued track of land which the Sea in process of time has washed away and left only the higher grounds… Others and I think…that they are formed from Shoals or Coral banks and of consequence increasing; and there are some who think they have been thrown up by Earth quakes.

But by the beginning of the nineteenth century it had become clear that while coral atolls might emerge in the deepest parts of the ocean, the living coral itself could not grow more than a hundred feet or so below the surface and had to have a firm foundation at this depth. Thus it was not imaginable, as Cook conceived, that sediments or corals could build up from the ocean floor.

Sir Charles Lyell, the supreme geologist of his age, postulated that atolls were the coral-encrusted rims of rising submarine volcanoes, but this seemed to require an almost impossible serendipity of innumerable volcanoes thrusting up to within fifty or eighty feet of the surface to provide a platform for the coral, without ever actually breaking the surface.

Darwin, on the Chilean coast, had experienced at first hand the hugh cataclysms of earthquakes and volcanoes; these, for him, were ‘parts of one of the greatest phenomena to which this world is subject’ – notably, the instability, the continuous movements, the geological oscillations of the earth’s crust. Images of vast risings and sinkings seized his imagination: the Andes rising thousands of feet into the air, the Pacific floor sinking thousands of feet beneath the surface. And in the context of this general vision, a specific vision came to him – that such risings and fallings could explain the origin of oceanic islands, and their subsidence to allow the formation of coral atolls. Reversing, in a way, the Lyellian notion, he postulated that coral grew not on the summits of rising volcanoes, but on their submerging slopes; then, as the volcanic rock eventually eroded and subsided into the sea, only the coral fringes remained, forming a barrier reef. As the volcano continued to subside, new layers of coral polyps could continue to build upward, now in the characteristic atoll shape, toward the light and warmth they depended on. The development of such an atoll would require, he reckoned, at least a million years.