Mays, 1887.] 



THE TROPICAL AGRICULTURIST. 



773 



of remaining under water and repressing inspir- 

 ation and respiration for two minutes, or at the very 

 utmost two and a half. But those viho know that 

 the blood is the life, and that it must, as it circulates 

 be ffrated, or lungs and heart will cease to act, 

 will be slow to believe in a staying power under 

 water of three minutes, far less of six. If such 

 dives have ever been really made, Hie record being 

 accurately ktpt, the conclusion must be that in 

 such cases the respiratory organs were in an ab- 

 normal condition, or that some means of obtain- 

 ing fresh air were adopted. It is not obvious 

 how the use of a nose-compressor (made of 

 horn, I believe,) could have aided the man 

 who made the long dive. The other "Arab" 

 alluded to by Capt. Donnan had an imperfec 

 diving dress which, it will be observed, was rather 

 an encumbrance than a help to him as a regular 

 diver, in which capacity he was only thoroughly 

 successful when he abandoned the adventitious aid. 

 Much service to (he pearl fisheries of Ceylon was 

 naturally expected from the class of European 

 divers who, by meaES of external air supplied to 

 them, can remain not minutes but hours under 

 water. But the hopes entertained have not been 

 realized. For the ordinary operations of rapidly 

 collecting and bringing shells to the surface, a 

 regular diving dress is as much of an impediment as 

 was Saul's armour to the shepherd lad who slew the 

 giant with the simple weapons of a pebble from 

 the brook projected by a sling. For exploring the 

 banks and reporting on their condition, more might 

 have reasonably been expected. But a thickly 

 mailed and heavy booted European diver, with 7 

 to 1) fathoms of water pressing on him, is no light 

 entity to walk over and inevitably crush the colonies 

 of molluscs. Sir Henry Ward, in his graphic ac- 

 count of his visit to one of the series of pearl 

 fisheries in his time, did not fail to notice the 

 heavy and awkward movements of the regular diver 

 under water, as contrasted with the lithe and rapid 

 action of the next to nude native professional. As 

 a matter of fact, Capt. Donnan, by the aid of a few 

 well-trained and experienced native divers, who not 

 only bring up specimens of the shells, but report 

 on the conditions they have observed below, (for 

 the divers keep their eyes open, — very wide open,) 

 is better able to judge of the state and pro- 

 spects of a bank, than he could be by any aid 

 rendered by men in cumbersome diving dresses. 

 Most useful are such men in exploring wrecks 

 and in carefully and patiently building up sub- 

 marine structures, such as our grand Colombo 

 breakwater. But there are limits to their func- 

 tions, and those limits are reached when it is 

 attempted to employ them in connection with pearl 

 banks or pearl fisheries. In calm clear weather, I 

 believe the bottom is distincly visible through seven 

 fathoms of water, (the average on the pearl banks,) 

 and with a good glass to aid the eye, so, also, I 

 should think, are most details of coral and algas, living 

 and dead shells, and even the movements occasionally 

 of such fishes as skates and " old women," destruc- 

 tive enough, in all conscience, but not to be 

 compared I suspect to the deadly operations of 

 the voracious whelks, who only want a small 

 chip on the edge of a shell, or the incautiously 

 prolonged opening of the lips of its prey to make short 

 work of the animal, whose nacre-secreting powers has 

 made it so famous and so valuable. For scientific 

 observation, however (observation which may lead 

 to important economic results), I should think the 

 electric light might be employed with advantage. 

 There is very much in "the life history" of the 

 pearl mussel (^vicula [Meleac/ritui] margarttifera 

 of LiNN.Tuis), which is obscure or utterly unknown. 

 We know that on banks with the proper con- 



ditions of depth of water and other circumstances, 

 but the bottom of which is merely sand, the 

 bivalves will not settle, because the ground pre- 

 sents no solid object to which the creature can 

 anchor itself by its byssus, or beard, an organ 

 which it has the power, often resorted to, 

 of throwing off and renewing. A sandy 

 bottom strewed profusely with coral or other rocky 

 fragments, capable of offering a steady resting- 

 place to the aggregated mollusks, presents the necess- 

 sary conditions, with, always, about seven fathoms 

 of water over the bank. So essential is this latter 

 condition that if ever the hitherto abortive ex- 

 periment of breeding pearl oysters artificially is to 

 succeed, it must be secured. Shallow estuaries, 

 the water of which has a warm temperature, such 

 as the edible oyster rejoices in, would, we now 

 know be fatal to " the pearl oyster." But all the con- 

 ditions of a coral-strewed bottom in seven fathoms of 

 water may be present, as they are in many places 

 between Aripu and Chilaw, and yet the pearl shells 

 will either never settle on them, or never settle 

 long enough or in sufficient numbers to render a 

 fishery of such banks profitable. Even on the 

 two iDanks on which the oysters do settle and 

 sometimes remain until they more or less attain 

 maturity (the full term of life being seven years, 

 but their fishing age ranging from 2J to 4 years), 

 the effects of currents by which the masses 

 of spat are driven hither and thither, and the 

 other conditions which lead the spat to settle, and 

 fix themselves and grow for a longer or shorter 

 period, — sometimes the whole millions vanishing 

 as suddenly and mysteriously as they came, — are 

 all wrapped in much obscurity and require patient 

 investigation. 



Of one thing my recent visit and observations have 

 convinced me, that amongst the main reasons why, 

 in the midst of all their capriciousness and pre- 

 carious, the Modregam bank just fished and the 

 Chevalpar now having so successfully dealt with 

 are such favourite resorts of the pearl oysters, is 

 the Untie quaniiiy of fresli icater, with all that it 

 contains of vegetable and animal matter suitable 

 as food for the animals, which several large 

 rivers pour into the bay of Silavaturai. The fresh 

 water, of course, floats for a long period over 

 the salt, and Mr. Twynam told me he has 

 dipped perfectly fresh water from the surface many 

 miles from the shore. No doubt, in periods of 

 extreme flood, the rivers may do harii? instead 

 of good to the oysters on the banks, by bringing 

 down such enormous quantities of alluvial matter, 

 that the bivalves are smothered in the resulting 

 mud. This effect, when it has occurred has been 

 easily seen and duly recorded, but I cannot at 

 this moment recollect if due prominence has been 

 given to the theory I venture to advance, or sup- 

 port, if it has been advanced, that under ordinary 

 circumstances the rivers which embouch into the bay 

 opposite the Modregam and Cheval Pars, which are 

 only about twelve miles from the shore, must 

 have an important influence for good : pi'obably 

 in modifying the temperature and quality of 

 the sea water with which the fresh gradually 

 amalgamates, but especially in the quantity 

 of vegetable and animal matter, (lani plants, 

 leaves, and flowers, fresh water algffi, earth 

 worms, insects of various kinds Ac,) they bring 

 down and which, first their own momentum and 

 then the currents carry over the bank and de- 

 230sit amongst the oysters. Such is the strong belief 

 forced on me, and I also feel that the Pearl Banks 

 of Silavaturai, the "buried city" of Anuradha- 

 pura, and the Great Kalawewa lake, are connected 

 together by a chain of most interesting physical 

 circumstances, to which further reference may 



