438 



NATURE 



[October 6, 1910 



from which Bloemfoiitehi draws its supplies, refuses to 

 settle clear, and cannot be effectively purified by sand 

 filters, which, however, are very soon choked by the 

 suspended clay. A remarkable improvement was effected 

 by precipitating with lime and permanganate, and filter- 

 ing rapidly through a mechanical filter, the deaths from 

 enteric fever falling from 83 per 10,000 in 1896 and 20 per 

 10,000 in 1904 to 275 per 10,000 in 1908. In view of 

 the necessity of increasing the plant, a tour was made 

 to inspect the chief purification plants both in Europe 

 and in America. England and the northern part of the 

 States do not show many e.xamples of river-waters of the 

 Modder type, and appear to be admirably served by the 

 " fool-proof " method of sand-filtration. But in Egypt 

 and in the southern States the author found many 

 analogous cases in which extraordinary results were 

 achieved by chemical precipitation followed by rapid 

 mechanical fiUration. He concludes that the extraordinary 

 rapidity of the mechanical filtration is accompanied by no 

 special risks of pollution when it is used intelligently in 

 conjunction with a chemical precipitation process, and that 

 in the case of non-settling waters, which can only be 

 purified by such a precipitation, the rapid mechanical 

 filtration is decidedly to be preferred on the ground of 

 efficiency combined with economy. The paper will be 

 read with interest by many who have been compelled to 

 limit their observations of water purification to the some- 

 what uniform conditions which prevail in the water 

 supplies of Great Britain. 



The American Journal oj Science for September con- 

 tains an account of an important series of researches upon 

 the complexity of tellurium, by Mr. W. R. Flint, of 

 Yale University. The material used amounted to 500 

 grams of the redistilled metal ; a series of five conversions 

 of the basic nitrate 2TeO,.HNO, into the dioxide gave 

 an atomic weight 127-45, with a maximum error 0-04. 

 The material was fractionated by repeatedly precipitating 

 the dioxide from solutions of the chloride by the addition 

 of a large excess of water. Four precipitations reduced 

 the atomic weight to 126-59, w-hilst ten precipitations gave 

 the value 124-32 for a fraction amounting to 23 grams. 

 This figure does not necessarily represent the lowest 

 possible value for the atomic weight, but it agrees well 

 with Mendel(5eff's prediction that the true value would be 

 123 to 126, and " is apparently the nearest approach which 

 has yet been made to the true atomic weight of the element 

 tellurium." The fractions less easily hydrolysed by water 

 were also worked up, and yellow to green substances were 

 isolated ; these gave negative results when tested for the 

 commoner elements, but gave nearly all the reactions of 

 tellurium, and many perhaps contain an unknown 

 homologue. 



The trials of H.M. second-class cruiser Bristol, com- 

 pleted on September 27, form the subject of an illustrated 

 article in Engineering for September 30. The Bristol is 

 the first British ship tried with other than the Parsons 

 type of turbine, her propelling machinery consisting of 

 Curtis turbines of a special character designed by the 

 builders, Messrs. John Brown and Co., of Clydebank. 

 This firm has taken up the Curtis turbine on account of 

 the following reasons : — (i) the potential advantages of 

 acquiring experience with a type of marine turbine capable 

 of using superheated steajn, as in land installations ; 

 (2) the attainment of economy at low powers, without the 

 disadvantage of very close-fitting parts, and the extremely 

 fine adjustments entailed thereby ; and (3) the simplifica- 



NO. 2136, VOL. 84] 



tion of the connections and general engine-room arrange- 

 ment, and also the expectation of attaining higher efficiency 

 by an increase in size of the individual propellers. With 

 characteristic thoroughness, the firm first constructed e.x- 

 perimental plant and conducted a lengthy research on 

 several modifications of the Curtis turbine, the results of 

 which are now embodied in the machinery of the Bristol. 

 It is a pleasure to record that the result of this policy is 

 that the Bristol on her official trials has secured the same 

 mileage per unit of water consumption as has been 

 obtained in the four ships of her class which preceded her, 

 these having Parsons turbines, embodying the inventor's 

 latest improvements at the date of their construction. As 

 this is the first Brown-Curtis installation, even better 

 results may be looked for as the experience of the makers 

 extends. 



The svndics of the University Press, Cambridge, have 

 entered into an agreement with the directors of the Chicago 

 University Press to undertake the publication and sale in 

 England and in the British colonies of books issued by 

 the Chicago University Press. This will apply to all 

 future publications and, subject to certain existing arrange- 

 ments, also to books already published. 



The October issue of the quarterly list of second-hand 

 instruments which he has for sale or hire has been pub- 

 lished by Mr. C. Baker, of 244 High Holborn, London. 

 The catalogue contains details of 1635 pieces of apparatus, 

 and is concerned with microscopes, surveying and draw- 

 ing instruments, telescopes, spectroscopic apparatus, as 

 well as instruments for use in the study of most other 

 branches of physics. Messrs. H. F. Angus and Co., 

 83 Wigmore Street, London, have also sent a copy of their 

 first catalogue of second-hand scientific apparatus and 

 accessories. This department has been added to the busi- 

 ness but recently, but the list shows that workers in science 

 will find already a good selection of instruments likely to 

 provide the apparatus of which they may be in search. 



OUR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in October : — 

 October 7. 5h. 6m. to 6h. 23m. Moon occults 5 Scorpii 



(mag. a'O. 

 ,, 10. iih. 7m. Minimum of A'gol (3 Persei). 

 ,, II. Meicuty at greattst elongation west and visible as 



a morning stir. 

 ,, 13. 7h. 56m. Mirimiim nf Algol (S Persei). 

 ,, 18-22. Epoch of the October shooting stars (Orioiiids, 



ladiant at 92° -f 15°). 

 ,, 26. I4h. 44m. tn ijh. 51m. Moon occults ri Leonis 



(mag. 3-6). 

 ,, 27. 22h. 52m. Yenus and Jupiter in conjunction, 



Yenus 0° II' N. 

 ,, 29. I3h. i6m. Mercury and Jupiter in conjunction, 



Mercury 0° 21' N. 



A Bright Meteor. — From a correspondent we have 

 received the following particulars of a bright meteor seen 

 at South Kensington during Mond.ay night, October 3 : — 

 Time, I2h. 50m. ; approximate path, from 310°, -4-35°, to 

 294°, -f35°; size, about one-third diameter of moon; 

 duration of flight, about three seconds ; no triiil ; colour, 

 whitish-yellow. 



REniscovERv of Brooks's Periodical Comet (18S9 V.), 

 igiod. — .\ telegram from the Kiel Centralstelle announces 

 that Brooks's periodical comet was rediscovered by Messrs. 

 Aitken and \Yilson, at the Lick Observatory, on Sep- 

 tember 28. Its position at 9h. i7-3m. (Lick M.T.) was 

 R.A. = i9h. 47m. 51S., dec. = 28° 8' 39" S., which agrees 

 closely with the ephemeris by Prof. Bauschinger men- 



