February 23, 1905 J 



NATURE 



595 



Prof. Callendar 

 Prof. A. Fowler ... 

 Mr. W. Shackleton. 



Lick Observers 



-Near Oropesa.< 



Algeria. 



Sir Norman Lockyer \ ,, nuM- 

 Dr.W.J. S.LocUyer-N^"Ph'''PP=- 



i>» r- r. T> .1 ville 



Mr, C. P. Butler ... I 



Mr. H. F. Newall. 



The Astronomer"! 



Royal I 



Mr. F. W. Dyson... | 

 Mr. Davidson ...J 



Egypt. 



Experiments on coronal 

 radiation. Photography 

 of the red and green 

 regions of the spectrum 

 of the chromosphere and 

 corona. 



Search for intra-mercurial 

 planet. Large scale 

 corona photographs. 

 Polarisation observa- 

 tions. Spectroscopic 

 photographs of chromo- 

 sphere and corona. 



Prismatic camera (three 

 prisms) photographs of 

 chromosphere & corona. 

 Large scale prismatic 

 reflector photographs of 

 chromosphere & corona. 

 Small scale photographs 

 of corona, 

 f Spectroscopic and polari- 

 ' \_ scopic observations. 



1 Photographs of the corona 

 on 4-inch and ij-inch 



! scales. Spectra of 



I chromosphere cS: corona 

 with Major Hills'sspec- 



( troscopes. 



/ Polariscopic observations. 



Corona photographs 



with Abney doublet. 



(Large scale photo- 

 \ graphs of the corona ?) 

 / Search for im ra-mercurial 



planets. Large scale 

 . .: corona photographs. In- 

 ] tegrating spectroscopic 

 ( photographs. 



One of the novelties that will be attempted during 

 this eclipse will be the photography of the eclipsed 

 sun by means of the three-colour process. The 

 camera that will be employed will probably be one 

 having three lenses, so that the exposures through 

 the three coloured screens can be made simultaneously, 

 the correct ratio of the exposures being obtained by 

 adjusting the apertures of the lenses. 



When it is considered that in addition to these 

 parties there will most probably be expeditions from 

 several other countries, such as Spain, Portugal, 

 Holland, France, Germany, Italy, Russia, Egypt, 

 &c., and probably one or two inore United States 

 expeditions, there is a great opportunity not only for 

 occupying a large number of different stations along 

 the line, but of gaining a quantity of valuable 

 material to enlarge our knowledge of solar physics. 

 William J. S. Lockyer. 



THE CEYLON PEARL FISHERIES.'^ 



LITTLE enough is done by the State in this country 

 in the matter of aiding scientific research, and 

 this is especially true of biological science. To this 

 attitude of indifference, or aloofness, we have grown 

 accustomed ; abroad it is a subject for uncomplimentary 

 comment. This attitude cannot be due to the convic- 

 tion on the part of our ministers that " science is 

 bankrupt," since when some great industry is 

 threatened by injuries which legislation is powerless 



1 " Report to the Government of Ceylon on ttie Pearl Oyster Fisheries of 

 the Gulf of IVlanaar." By W. A. Herdman, D.Sc, F.R.S., &c. Part ii. 

 Pp. viii-t-300. (London: The Royal Society, 1904.) 



Prof. Turner 

 Mr. Bellamy 



Lick Observers 



to check, or some pest is threatening the welfare of 

 the cominunity, the aid of the man of science is at 

 once invoked. 



The Pearl Fishery Commission is a striking example 

 of the intervention of the State to aid a crippled in- 

 dustry by calling in the aid of the biologist. 



The series of barren years alternating in some 

 mysterious way with years of plenty puzzled those 

 engaged in this fishery for tnore than two centuries, 

 and, inoreover, seriously reduced the profits of the fish- 

 ing. To fathom this strange uncertainty, and if 

 possible to find means whereby more uniform harvests 

 could be ensured, the Government submitted the matter 

 to a commission of inquiry, which has been held 

 under the auspices of the Ceylon Government. The 

 results of this inquiry have abundantly justified those 

 responsible for its inception, and should do much to 

 establish the advisability of instituting inquiries into 

 other problems to which we could point that can only 

 be dealt with by trained and experienced biologists. 



The second part of Prof. Herdman 's report to this 

 commission in no wise suffers by comparison with the 

 first volume. It is a very mine of information, yield- 

 ing rich lodes of fact without the trouble of any pre- 

 liminary crushing or sifting. 



This report opens with a luminous review of the 

 history of the principal fisheries from iSoi to the pre- 

 sent time, and should prove of the highest value to 

 those engaged in pearl fishing in future, for the causes 

 of the rise, zenith, and decline of the different fisheries 

 between these dates have been analysed and tabulated. 

 It is now established beyond doubt that the normal 

 life of the pearl oyster does not average more than 

 five years, and that these, especially to an animal so 

 peacefully disposed as an oyster, are full of catastrophes 

 and rumours of catastrophes ! 



By way of illustration as to the truth of this, we may 

 well select an instance or so froin this report. On the 

 " Kondatchi Paar " in March, 1902, there were about 

 5,750,000 oysters. By March, 1903, these had been 

 almost entirely wiped out of existence — eaten by star- 

 fish ! File-fishes and enonnous rays also show an in- 

 satiable appetite for oysters, and in the course of a 

 few months will devour millions! Not seldom these 

 oysters are smothered or killed by the invasion of 

 hordes of young of their own species. But this is not 

 all. Shifting sands may overwhelm incredible hosts, 

 and millions are swept away by currents. 



Man, says Prof. Herdman, " can do comparatively 

 little to mitigate the severity of such influences as ^tell 

 against the life and prosperity of the Pearl Oyster." 



But it is just because he can do so little that there 

 is so great a need of a vigilant and intelligent watch 

 being constantly kept on the different fishing grounds. 

 To a very considerable extent, Prof. Herdman has 

 shown that man can make good these ravages, or 

 snatch the remnant at least of a disappeartng host 

 from destruction. His plan is to transplant young 

 oysters from beds known to be dangerous into more 

 sheltered areas. This rescue work is to be further 

 turned to account bv using the waifs and strays, which 

 are to be garnered by l:he inspection vessel, for re- 

 stocking old beds, where they may grow and thrive— 

 and become infected by the chosen parasite to keep up 

 the growth of pearls of great price ! 



To ensure this infection is one of the problems which 

 Mr. Hornell, the inspector of fisheries, is to solve. 



The life of the pear! oyster is, as we have remarked, 

 about five years, and it 'is from those of this age that 

 the finest pearls are obtained. Herein lies a danger, 

 since there is always a strong temptation to delay fish- 

 ing as long as pos'sible to ensure big pearls. Unless, 

 as' Prof. Herdman points out, these beds be carefully 

 watched, one of the many catastrophes which attend 

 pearl oysters may carry off this precious crop before 



NO. 1843, VOL. 71] 



