148 



NATURE 



[December i, 1910 



■fluenced b}' a coloured slide than by one without colour. 



Bees which have been accustomed to visit a certain colour 

 tend to return to it habitually — they exhibit colour-fidelity. 



But this habit does not become obsessional, since they 

 •quickly learn not to discriminate between colours when 

 this is for their advantage." 



In his report on marine biology, included in the adminis- 

 tration reports of Ceylon for 1909, Dr. A. Willey states 

 that hopes have been entertained of rendering the southern 

 division of the Mannar pearl-oyster fishery — more especi- 

 ally the so-called " Chilaw paars," which were the head- 

 quarters of the industry during the sixteenth century — 

 once more productive. The results of recent observation 

 tend to confirm Prof. Herdman's suggestion that most of 

 the Mannar oysters are not bred in situ, but are carried 

 by currents from the coasts of southern India — a con- 

 clusion which is of the most far-reaching importance in 

 regard to the future of the pearl-fisheries. " Many years 

 may elapse before anything like complete knowledge can 

 "be acquired concerning the physiology of the pearl banks. 

 The great question which compels attention at the present 

 juncture is that of the forced production and preservation 

 of pearl oysters as against their natural propagation when 

 left to themselves. It is felt that something must be 

 <ione, and, from the rather misleading analogy of the 

 edible oysters, that something can be done. And this 

 ■conviction is fortified by the fact that something is being 

 done with the same species in Japan, although it is prob- 

 ably a distinct local race adapted to a different environ- 

 ment. It still remains to be seen whether interference 

 ■with the natural sequence of events will prove useful or 

 profitable under the very special conditions that prevail in 

 the Gulf of Mannar. It is only within the last few years 

 that any attempt has been made to fathom the mystery 

 by the accumulation of facts." 



The question of utilising wind power in country districts 

 is so imfKDrtant that special interest attaches to the collec- 

 tion of statistics showing the frequency of winds of given 

 velocities. In the Agricultural Journal of the Cape of 

 Good Hope (No. 3) Dr. Sutton gives such a table for East 

 London, and compares it with a similar table previously 

 ■drawn up for Kimberley. It appears that at East London 

 the wind is commonly too strong for the ordinary type of 

 windmill ; there is a vast amount of energy in the winds 

 ■of the south-east coast of South Africa awaiting exploita- 

 tion, but the mechanical difficulties appear to be great. 



A NUMBER of determinations of the amount of arsenic 

 present in soil, plants,, fruits, and animals are recorded 

 in a paper by Dr. Headden in the Proceedings of the 

 Colorado Scientific Society, vol. ix. In the virgin soils 

 examined no fewer than 2-5 to 5 parts per million were 

 found, whilst the subsoils contained even more, sometimes 

 as much as 15 parts per million. Orchard soils where 

 arsenical sprays have long been in use may contain 10 to 

 28 times these quantities, and yield appreciable amounts of 

 arsenic compounds to water. Crops grown on these soils 

 and fruits from the trees all contained arsenic, and it was 

 also readily detected in the urine of three persons who had 

 ■eaten quantities of these fruits. 



The United States Department of Agriculture has of 

 late been carrying out careful investigations on food and 

 nutrition. Bulletin 227 deals with calcium, magnesium, 

 and phosphorus in food and nutrition. It appears that a 

 healthy man accustomed to a full, mixed diet requires for 

 maintenance of phosphorus equilibrium about 1-5 grams of 

 phosphorus, or nearly 3-5 grams of phosphoric acid, per 



NO. 2144, VOL. 85] 



diem, and the organic combinations of phosphorus seem to 

 be best adapted for the purpose. The calcium require- 

 ment is equivalent to about 07 gram of calcium oxide per 

 diem. Reference is made to the value of milk in supply- 

 ing these requirements. The work has been carried out 

 by Prof. Sherman and Messrs. Mettler and Sinclair, of the 

 Department of Chemistry, Columbia University, and full 

 details are given of the analytical methods and of the 

 metabolism experiments. Circular 102 gives a list of the 

 bulletins, &c., dealing with the subject issued by the 

 Department. 



Capt. M. PisciCELLi contributes a well-illustrated article 

 on Lake Bangueolo to the October BoUettino della Societa 

 Geografica Italiana, in the form of a letter .to the secre- 

 tary, dated at Abercorn, May i, 19 10. The hydrographical 

 conditions of this great complicated maze of water, marsh 

 and islands are described, with notes on the natives and 

 on the fauna of the region. 



Mr. Ellsworth Huntington continues his investiga- 

 tions on the lines of his fascinating " Pulse of Asia." In 

 the September number of the Bulletin of the American 

 Geographical Society he analyses the data collected by Mr. 

 H. J. L. Beadnell respecting the Libyan oasis of Kharga, 

 and claims that they indicate a succession of climatical 

 changes during the last 2500 years that are in close agree- 

 ment with the hypothetical " pulsations " of climate in 

 eastern and central Asia during the same period. 



The Liverpool Geological Society may be congratulated 

 on the opening number of the eleventh volume of its 

 Proceedings, which contains a spirited address by Prof. 

 J. W. Judd, F.R.S., on " The Triumph of Evolution : a 

 Retrospect of Fifty Years." Prof. Judd has always 

 brought his personal knowledge of the pioneers of geolotjy 

 to aid him in stimulating research in newer generations. 

 He has systematically upheld the claims of Lyell as an 

 original observer, and as one of the masters who paved, 

 the way for the general acceptance of evolution in the 

 natural world. In the present address the relations of 

 Lyell and Darwin, and the final " triumph of evolution " 

 resulting from the work of Darwin and Wallace, are 

 pointed out with vigour and characteristic' clearness. This 

 part of the Proceedings also contains papers that maintain', 

 the high standard set by the society in the explanation of: 

 local geological features. 



The scientific investigation of the German colonial 

 possessions in Africa proceeds steadily, and in the Mitteil- 

 ungen aiis den deiitschen Schutzgebieten results "are being 

 regularly published. The last number (Heft. 3, Band 23) ij 



contains five articles dealing with German South-West 

 Africa. One deals especially with the Auin, a Bushman 

 tribe of the Middle Kalahari Desert, which occupy a dis- 

 trict in the eastern boundary of the territory on the border 

 of Bechuanaland. Their habits and customs, weapons, 

 modes of hunting, games, and other information relating 

 to this small tribe, which are said to number some 3000, 

 are described and illustrated. A map. on a large scale 

 attached to the same number shows the position to the 

 south of Kilimanjaro which has been set aside as a re- 

 served territory for those of the Masai tribe who are on 

 the German side of the Anglo-German boundary line. The 

 reserve contains some 2500 square miles, and lies to the 

 west of the Pangani River. 



The results of the magnetic observations made at tli 

 Central Meteorological Observatory of Japan during 1907 

 appear, and are discussed, in part ii. of the annual reporf 

 now published. The observatory is situated at an altitud 



