OCTOBKR [4, 1887.] 



SCIENCE. 



187 



The great pearl-fishery of Ceylon is carried on at stated periods 

 on the banks of the north-west coast of the island, at the entrance 

 to the Gulf of Manaar. As it is a g-overnment monopoly, great care 

 is now taken to give rest to the fishery, so as to allow the oysters 

 to attain a maturity of five or six years, which will warrant a rich 

 yield of pearls. There is a prospect of a good pearl-fishery in 

 1888 ; and it is confidently expected that as many as 300,000,000 

 oysters will be fished, requh'ing every boat and every diver pro- 

 curable in Ceylon and southern India. The small, thin shells of 

 this oyster {Aviciila fucata), unlike the heavy, true mother-of-pearl 

 •oyster {Meleagrina margaritifera), have little or no commercial 

 value, and are chiefly burnt for lime. 



When a fishery is proclaimed, the arid sands at Arippu, on the 

 north-west coast, become, as it were, a bustling town of tents, 

 filled with people of varied races and occupations, including boat- 

 men from the Coromandel coast, pearl-dealers from India, Malaya, 

 and China, with the accompaniments of merchants and traders of 

 all classes. The Ceylon Government takes as royalty two-thirds of 

 the oysters gathered, which are sold by auction at the close of each 

 day's fishing. Only a limited number of boats and divers are 

 licensed to fish. 



The fishing can be carried on only during the very calmest period 

 of the north-east monsoon, — February to April. In these months 

 the wind blows off the land during the night, and off the sea during 

 the day, which enables the large fleet of fishing-boats to reach the 

 pearl banks by daylight on each morning, returning with their 

 cargoes shortlv after noon. The boats, containing twenty men 

 (half divers), are divided into two fleets, which go out to their work 

 on alternate days. The price realized for the oysters varies from 

 ^2 to £"] the thousand, the value depending to a great extent on 

 that of a sample of 5,000 lifted in the early part of the fishing. 

 The contents of the moUusk being allowed to decay before the 

 pearls can be obtained, the stench is horrible. The congregations 

 of pearl-dealers, petty traders, official subordinates, and laborers on 

 the shores, are enormous. 



About the island of Borneo there is a good deal of fishing for 

 pearls, which are found in a thin, flat, pinkish-shelled oyster, known 

 locally as salesiep. This lives only in shallow brackish water at the 

 mouths of rivers. Several boats rendezvous at the same time and 

 place to frighten the crocodiles and sharks. Twenty or thirty per- 

 sons will be in the water at once, diving, splashing, laughing, and 

 shouting, and bringing up three or four shells at a time : extra yells 

 from all hands salute a rather larger find than usual. Very few of 

 the pearls obtained are of any value individually : they are chiefly 

 seed-pearls, which are sent to China, where they are pounded up, 

 made into powder, and this is swallowed by ladies who desire to 

 improve their complexion ; at least, such is the story. From British 

 North Borneo the value of the pearls exported in a year is ;£5oo. 

 Pearls of a very high price are not infrequently to be bought at 

 Sandakar, but they come principally from the islands of the Sooloo 

 Archipelago. The largest ever seen there was valued at _£ 1,600. 



The formation of pearls is not limited to the bivalves: they are 

 produced on several univalves, especially on the Sironibs and Tur- 

 binellas, but are more rare in these than in the bivalves. About the 

 Bahamas group of islands and keys, the shells of the king, queen, 

 and common conch were much sought after for sale to the cameo- 

 cutter, but the fashion for cameo jewelry has passed away. The 

 common conch is the ordinary pink-mouthed shell so frequently 

 seen in milk-shops. It furnishes the rare pink pearls, so much 

 appreciated, and these are exported from the Bahamas to the value 

 of about ^3,000 annually. Some fine collections of these pink 

 pearls, set and unset, were shown at the Fisheries and Colonial Ex- 

 hibitions in London. 



It was once thought that no other pearls than those produced by 

 the pearl oysters could obtain a rank among gems ; but some of the 

 river-pearls found in species of mussels (6^«/i?j) compete closely 

 with those from the Mollusca of the ocean. These river-pearls are 

 found widely diffused in France, Saxony, Bavaria, Bohemia, and 

 Silesia, as well as in the lochs and rivers of Scotland, Ireland, and 

 Wales. In China, the rivers of Manchuria furnish a good many. 

 Delegates from the royal household look out for the best of these 

 pearls there for the ladies of the imperial court. 



In many of the Scotch rivers old men, women, and children may 



be seen wading about the shallow fords ; and, when they discover 

 a collection of mussels, they thrust down long sticks split at the 

 ends, and bring up the mussels wedged in the slots. In the shal- 

 low waters of the Dee, the boatmen look down into the water with a 

 tin having a glass bottom, and when shells are discovered, they are 

 brought up by a kind of dredge, or scoop, and frequently some fine 

 pearls are obtained. 



These pearl mussels are also found in most of the small streams 

 of the Province of Quebec, and in the districts bordering on the 

 lower St. Lawrence. The streams most abounding in pearl mussels 

 are but little known, except to Indians and backwoodsmen, who 

 are careful in guarding the secret of where these mollusks are 

 found. 



Occasionally a party of pearl-seekers may be seen paddling in 

 ai bark canoe, and portaging through a very wild region. After 

 opening several thousand mussels, they will only succeed in secur- 

 ing a few good pearls. These vary in color from white to dark 

 brown : the white are appreciated for their rarity, and the pink on 

 account of their peculiar brilliancy. In form they are generally 

 round or spherical, and have a hard skin with an iridescent or 

 nacreous hue. 



It would lead to too much detail to pass under review the various 

 pearl-fisheries of the Australian coasts, the Eastern Archipelago, 

 and the Pacific Islands, where the unclothed native divers have to 

 brave the attacks of sharks, cephalopods, and other dangers. They 

 especially dread the stings of the jelly-fish, which they say are 

 speedy death to them. Enough has, however, been stated to show 

 the importance of this wide-spreading industry of hunting for gems 

 and precious stones. Fine collections of these are frequently brought 

 before the public to feast their eyes on, as at the recent Colonial 

 and Indian Exhibitions in London, and those at Amsterdam, Paris, 

 and elsewhere. 



At the Fisheries Exhibition in London, a firm of Parisian jewellers 

 showed, among others, a very choice five-row necklace of 355 

 selected Oriental pearls, weighing 2,570 grains ; a matchless and 

 unique necklace and parure of Scotch pearls ; a very important 

 black pearl necklace, composed of 39 pearls, weighing 1,020 grains; 

 a round pearl of 96 grains, being one of the finest pearls known, 

 and worth £20 a grain ; a very important collection of Oriental 

 pearls, composed of 3,345 grains original, such as are most prized in 

 Bombay, besides black, pink, yellow, and gray fancy pearls. 



MENTAL SCIENCE. 



Recent Observations in Hypnotism. 



The great attractiveness that the study of the varied and inter- 

 esting phenomena of hypnotism possesses for the French physi- 

 cians has been often noticed. Not a month passes without some 

 new and often startling contribution. The leaders in this move- 

 ment are eminent scientific specialists, and have been cautious 

 about accepting all the strange doings of excitable subjects as per- 

 fectly genuine. They appreciate the readiness with which a shrewd 

 patient can deceive the unsuspecting observer, and insist upon the 

 most exacting tests, arranged with a full knowledge of the sources 

 of error to be eliminated. Under such a scrutiny, many alleged 

 marvels have taken on a less miraculous aspect, and many startling 

 interpretations shown to lack validity. Amongst the oldest claim- 

 ants to scientific recognition in this field is the statement that a 

 magnet has a peculiar effect upon hypnotic subjects. Sometimes 

 the application of a magnet causes trembling and tingling ; again it 

 is said to produce contractions of limbs, and cause such a contrac- 

 tion to pass from one side of the body to the other ; and so on. 

 Professor Delboeuf, a successful observer in this field, has very in- 

 geniously tested these claims, and made much progress towards 

 showing their falsity. He experimented upon a boy of fourteen, an 

 experienced hypnotic subject susceptible to ' magnetic ' influence. 

 In the preliminary trials Professor Delboeuf had a true magnet and 

 a wooden magnet made to look alike, and each fitting in a case 

 alike for both magnets. He handed the boy the case containing 

 the true magnet, but nothing happened : as soon as the magnet 

 was drawn out, he developed a violent contracture, his usual symp- 

 tom. 



