Emily and Grace, as well as Oliver and I, took great interest in watching the proceedings I have described. I asked Mr Hooker how pearls come to exist.

“Oh, I have read somewhere,” exclaimed Emily, “that they are produced by a kind of dew which falls from heaven into the salt water, where the oyster swallows it, when it hardens and forms the beautiful white object we call a pearl.”

“A very poetical notion, Miss Emily,” observed Mr Hooker; “but in reality pearls are identical with the substance which we call mother-of-pearl, which lines the shell of the oyster. It is, indeed, the result of disease. When any substance intrudes into the shell the animal puts forth a viscous liquor, which agglomerates and hardens till the pearl is formed. It is said, indeed, in some places, that the divers pierce the shells of the oysters, and thus increase the number of pearls. It has also been discovered that oysters which have been pierced by a certain small marine worm have invariably pearls within them. The oyster, to defend itself from the worm, covers the hole with a substance which becomes as hard as the shell, and brilliant as mother-of-pearl.”

A breeze springing up towards evening, we proceeded on our voyage, followed by the boats, which also shaped a course for the Aru Islands. In the course of the next day we came in sight of a small rocky island with high cliffs, off which we espied a couple of Chinese junks at anchor. As the island was not much out of our course, we stood towards it, keeping the lead going for fear of reefs. The water, however, was deep close up to the rocks. The cliffs completely overhung the sea, and we observed within them numerous hollows and caverns. On getting nearer, we saw that several boats belonging to the junks were lying directly under the cliffs. As the wind fell, we came to an anchor, for the sea over which we were now sailing was so shallow, that we could anchor in calm weather in almost any part of it.

A boat was lowered, and Mr Hooker invited us to accompany him. As we passed near the Chinese junk the crew hailed us, and Mr Hooker, who understood a little Chinese, remarked that they seemed very angry with us.

“They think, probably, that we have come to search for edible birds’ nests, which they themselves are now collecting,” he observed.

“Edible birds’ nests?” exclaimed Emily and Grace together. “Do you mean to say, Mr Hooker, by that, that there are birds’ nests fit to eat?”

“The Chinese not only think them fit to eat, but esteem them great delicacies,” observed Mr Hooker. “These junks have come all the way from China to collect them, and if they manage to get back without being plundered by pirates, or sent to the bottom by storms, they will make an enormous profit by the voyage.”

Mr Hooker hailed the junk in return, and told the men that they need not be alarmed; that we did not come to interfere with them, but only prompted by curiosity to see what they were about. As we got nearer we saw the entrance to a cavern, into which we pulled. A far from pleasant odour issued from it, while ahead there was an inky darkness, which the keenest eye could not penetrate. As we proceeded, however, we observed a bright light coming from the interior, which showed us a boat with a couple of Chinese in her, one of whom was holding a torch; while another man, by means of a ladder, was mounting up a narrow ledge of rock on the side. Overhead huge bats flitted round us, while on every side the tiny chirp of innumerable birds was taken up and echoed from seemingly a thousand voices throughout the cavern. Above the head of the Chinese appeared a number of nests, something in the shape of large deep spoons without handles, split in half longitudinally, smaller than the ordinary swallow’s nest. They were placed, without any order apparently, on every spot where a slight projection of the rock afforded a foundation. The Chinese, like their friends on board the junk, began to abuse us for coming to interfere with their occupation. Mr Hooker, however, soon pacified them, and offered them some money for a few of the nests, that we might examine them. This brought them at once into good humour, and they very readily sold us a dozen or more of the nests, though I thought the price for birds’ nests a very high one. A number of birds like swallows were flying in and out of the cavern. They had the flight of swallows; indeed, Mr Hooker said they were a species of swallow. They were about the size of robins or sparrows; their breasts white, their wings grey, and their backs and the feathers of their tails shining black. On examining the nests which we had purchased, we found that they were composed of a gelatinous substance something like isinglass.

“This is the substance,” Mr Hooker told us, “that the Chinese make into broth. They are packed, however, just as they are cut from the rock, and carried to China. There they are cleansed from all extraneous substances, and are then boiled or stewed, every particle of dirt being thus more completely removed; and then, with a mixture of spices, they make a transparent, delicate-looking jelly, although, without the spices, they have little or no flavour.”