388 



NATURE 



[July 6, 191 6 



After many vicissitudes and much conflict of 

 opinion, a water-supply scheme for Aberdeen has been 

 definitely laid down, and although some time will 

 necessarily elapse before the undertaking can be 

 carried out in its entirety and the town enjoy the full 

 advantages of the additional supply, it is recognised 

 on all sides that the settlement of the vexed question 

 is a matter for congratulation. The present supply 

 is drawn from the Dee, and, despite strong advocacy 

 of the merits of the Avon and the Dj'e, the future 

 supply ' will continue to be drawn from the same 

 source, though from a point some distance further 

 upstream. The new intake will be at Cairnton, 

 on the left bank of the river, twenty miles above 

 Aberdeen. One of the principal objections raised 

 against the Dee scheme was that, before interception, 

 the stream passes through several populous districts, 

 such as Braemar, Balmoral, and Ballater, which must 

 inevitably cause some degree of pollution. On the 

 other hand, the wide, shallow, and pebbly bed of the 

 river lends itself admirably to the oxidation of its 

 waters. It has been felt preferable not to rely merely 

 on filtration and storage, but to bring about further 

 purification by the excess lime treatment. A section 

 of this work has already been installed, and is 

 described, with illustrations, in the Engineer of 

 June 23. The population to be supplied with water 

 numbers 170,000, and the average daily consumption 

 per head is computed at 40 gallons. The new scheme, 

 as a first instalment, will provide 85 million gallons 

 per day, and afterwards an additional i^ million 

 gallons per day. 



OVR ASTRONOMICAL COLUMN. 



A June Meteoric Display. — Mr. W. F. Denning 

 writes from Bristol :^" On the evening of June 28, 

 after a cloudy, oppressive day, the atmosphere cleared. 

 On going out into my garden to commence observa- 

 tions at about 10.25 G-M.T. , I almost Immediately 

 saw that a very rich and unexpected display of 

 meteors was in progress. 



"Continuing to watch until 12.15, ^ saw fiftj^-five 

 meteors, including many fine ones. Then clouds 

 interrupted, but these had drifted away and left the 

 sky clear again at 12.45, ^"d fourteen additional 

 meteors were seen in half an hour. 



"The radiant was at 230^ + 54°, and there seemed 

 to be a well-marked companion centre near ^ Bootis 

 at 223° + 41°. The meteors were slow, and all the 

 brighter ones left evanescent trains of sparks. The 

 shower seems quite unknown, but there are rich 

 radiants in Quadrans on January 2 and October 2." 



The Visibility of Stars in Daylight. — Among other 

 interesting items, a note in the Observatory (June) 

 records that Sirius was seen with the naked eye by 

 Mr. A. E. M. Fleming one minute before sunset on 

 April 18. It may be stated here that M. Bigourdan 

 has now obtained grounds for believing that the 

 observation referred to in Nature, June 15, should 

 really be ascribed to Peiresc (Cotnptes rendus. No. 24). 



The Large Meteorite of February 13, 1915. — This 

 object fell in the Chusan Archipelago, near Video, and 

 an interesting description of the facts attending its 

 fall, by Mr. W. F. Tyler, appears in the Journal of 

 the Royal Asiatic Society (vol. xlvi., 19 15). Mr. 

 Tyler alludes to many of the observations and dis- 

 cusses the real path, but the data were somewhat con- 

 flicting, and he found it impossible to harm'onise 

 them and derive a perfectly trustworthy result. He 

 concludes that the meteorite probably exhibited a 

 curved flight, being directed from N.N.E. at first and 



NO. 2436, VOL. 97} 



from N.W. towards the end. As to the actual dimen- 

 sions of the meteor, Mr. Tyler concludes that the 

 incandescent mass at one point of its path was 1500 ft. 

 in diameter, while at the end it had declined to 80 ft. 



Mr. Tyler has done the best he could with dis- 

 cordant materials, but it is far easier to assume that 

 the obviously rough observations were wrong than 

 that the meteor had a very devious course. The writer 

 would prefer to adopt a straight course of about 

 60 geographical miles from N. by W. 



As to the diameter, the actual nucleus was probably 

 not more than two or three feet in diameter. It 

 is well known that meteoric bodies when incandescent 

 appear enormously larger than they really are. Thus 

 the meteorite which fell near Wigan on October 13, 

 1914, gave a brilliant illumination and thunder-like 

 reports over a wide area, though it only weighed 

 33 lb. when afterwards discovered. 



The Motion of the Nuclei of Comet 19 15^ 

 (Taylor). — In a series of measures of the nuclei of, 

 Taylor's comet, made at Bergedorf by H. Thieler 

 between February 19 and April 3, the distance showed; 

 little change, but the position angle varied consider- 

 ably. The observation gave a period of about thirty 

 days. If this is considered to be a rotational motion 

 the total mass of the comet would be about 10-^' 

 (Astronomische Nachrichten, No. 4846). 



On Centre — Limb Shifts of Solar Wave-lengths. 

 — An important memoir dealing with this subject, by 

 Mr. J. Evershed and Dr. T. Royds, appears as 

 Bulletin No. xlix. of the Kodaikanal Observatory. 

 The alterations of wave-lengths of certain iron lines 

 have been studied in greater detail over the sun's 

 disc, and it appears that they begin to be measurable 

 not far from the centre (o"3 of the radius). Thus the 

 displacements cannot be due to differential pressure 

 effects. The Inverse relation between the limb shift 

 and centre shift Is held to indicate that they have a 

 common origin. The authors prefer to seek the cause 

 In line-of-slght motion rather than In anomalous dis- 

 persion, although recognising the possibility of basing 

 thereon an attractive explanation. The Doppler effects 

 would result if there exists a general motion directed 

 away from the earth ,all over the disc. A crucial test 

 of the hypothesis, It is suggested, would be afforded 

 by measures of lines in the spectrum of that face of 

 the sun reflected from the planet Venus. 



METALLOGRAPHIC METHODS IN 

 AMERICA. 



TN a paper on "A Metallographic Description of 

 -»■ Some Ancient Peruvian Bronzes from Machu 

 PIcchu," Mr. C. H. Matthewson, in the American 

 Journal of Science (No. 240, December, 1915), gives 

 an interesting account of the detailed application of 

 modern metallographic methods to the study of ancient 

 metal objects with the view of arriving at an insight 

 into the methods of working employed by those who 

 fashioned the various objects. Some work of this 

 kind has already been done by Garland, Hadfield, and 

 Rosenhain, but the present paper carries the piatter 

 further, for the author has carried out a somewhat 

 extensive series of experiments on the behaviour of 

 the tin-copper alloys under cold and hot working and 

 annealing, in order to arrive as closelv as possible at 

 the precise mode of treatment which each of the 

 thirty-three objects examined had undergone. While 

 in general terms it has always been possible to deter- 

 mine from a microscopic examination of such an 

 object whether it has been cast or wrought, Matthew- 

 son endeavours to carry the matter further and to 



