April 27, 19 16] 



NATURE 



189 



unsafe water, although no conclusive evidence in the 

 way of figures is brought forward to prove it. Indeed, 

 throughout the paper, which gives in considerable 

 detail the results of tests made on multiple filtration 

 plants in different parts of the \\x5rld, there is no men- 

 tion of any tests being made for B. coli. 



The Health of Munition Workers' Committee has 

 issued a memorandum on special industrial diseases 

 in which it is stated that the work of certain industrial 

 processes entails risk of serious, and possibly fatal, 

 illness from exposure to lead, ethane tetrachloride, 

 nitrous fumes, and certain explosives, whilst contact 

 with trinitrotoluol, tetr\i, mercury fulminate, and cer- 

 tain lubricating and cooling liquids used in metal 

 turning may produce dermatitis. The provision of 

 facilities for the prompt treatment of all cases of sick- 

 ness and injury is recommended. Operatives engaged 

 in manufacturing or handling trinitrotoluol have been 

 found affected with unusual drowsiness, frontal head- 

 ache, eczema, and loss of appetite. The symptoms 

 I are generally slight at first, and disappear when ex- 

 i posurc ceases, but in exceptional cases sudden collapse 

 i may occur after a few hours' work on a hot day. 

 I The symptoms are intensified by continued exposure, 

 i and in a few cases profound jaundice and even death 

 i have resulted. T.N.T. may be absorbed by the lungs, 

 ! skin, or digestive tract, in the form of vaf)Our or 

 ! dust, and certain preventive measures are specified. 



Bllletin No. 266 of the Scientific Papers of the 

 , Bureau of Standards, by Messrs. Cain, Schramm, 

 j and Cleaves, deals with the preparation of pure iron 

 and iron-carbon alloys. The authors have worked 

 1 out methods of producing laboratory samples of iron- 

 j carbon alloys of a ver)' high degree of purity ; sources 

 of contamination of melts and means of eliminating 

 1 them are described ; a method of preparing magnesia 

 of a satisfactor)' degree of purity for making crucibles 

 to be used in work of this kind has been developed; 

 1 and a procedure for making small ingots, which are 

 sound and free from blowholes, without the use of 

 deoxidisers, has been worked out. A series of iron- 

 carbon alloys containing 9996 per cent, of the two 

 , elements has been prepared to serve as a basis for 

 ' the redetermination of the iron-carbon equilibrium 

 diagram. 



In Bulletin No. 60 of the Technological Papers of 

 j the U.S. Bureau of Standards, H. S. Rawdon 

 j describes the microstructural changes accompanying 



the anneahng of cast bronze (Cu88, Snio, Zn2). The 



alloy is first brought into physico-chemical equilibrium. 



The dendritic structure persists until heated for ap- 

 I proximately two hours at 800° C. The absorption of 

 j the eutectoid depends much on how the sample cooled 

 I on freezing. No evidence was found suggesting a 

 \ change of crystal size of cast samples which had not 



been distorted in any way. Recr>stallisation, includ- 

 Iing twinning, was found onlv to follow distortion or 

 jits equivalent. Metal cooled suddenly from the molten 

 I state behaves similarly because of the high internal 

 [stresses resulting. 



Messrs. Cassell and Co., Ltd., have ready for 

 .^-abhcation " Alfred Russel Wallace : Letters and 

 Reminiscences," by J. Marchant. The volume will 

 :»ntam a number of hitherto unpublished letters, 

 -emmiscences from various friends, and a sketch (from 

 i« son and daughter) of Dr. Wallace's home life. 

 ine evolution of the idea of natural selection is traced 

 |P to the time when the papers on the subject bv 

 'an^-m and Wallace were communicated to the 



nnean Society-, and Dr. Wallace's other scientific 



ork is dealt with in the volume. 



OUR ASTRONOMICAL COLUMN. 

 The Planet Mercury, — This planet will be at 

 greatest E. elongation on May 12, 21° 36' E. from the 

 sun. It will continue above the horizon about two 

 hours after sunset. Maximum conspicuousness occurs 

 several days before the elongation. 



Comet 1916a (Xeujmin). — Observations, including an 

 arc of thirt}-seven days (February' 27-April 4), have 

 been employed by M. J. Braae in calculating a new 

 orbit for this comet. The second and third places are 

 based on observations made at Bamberg (JNIarch 23) 

 and Xeu Babelsberg. The modifications of the earlier 

 orbit are all in the direction of the Berkeley orbit 

 noted last week, consequently the differences between 

 the respective ephemerides have been considerably re- 

 duced. According to Copenhagen Postcard No. 17 the 

 new orbit is : — 



T=i9i6 March 11-2350 G.M.T. P = 3oo8-8 days (550 y. 

 /x = 645i63" 



Epoch 1916 Jan. o"s G.M.T. Equinox 1916 "o 



Mo=347° 19' 24'5'' »=I93° 43' I77" 



<i> = 34' 43' 47" ft =327^ 30' 59"6|^ 



Log a= 0-493559 / = 10° 39' 530" 



Ephemeris (Messrs. J. Braae and J. Fischer-Peter- 

 sen), Greenwich midnight : — 



April 28 



30 

 May 2 



4 

 6 



h. m. s. 

 10 20 36 



24 59 



29 24 



33 51 

 38 21 



9 41-9 

 10 107 



10 387 

 " 5-9 



11 32-3 



Log A April 26, 9-7979, May 4, 98386 



Observations made at the Hill Observatory, Sid- 

 mouth, on April 20 and 22, were represented by this 

 ephemeris within the limits of accuracy attainable in 

 the measures. On April 22, the sky being especially 

 clear, the comet still showed a considerable diffused 

 coma and a feeble condensation was glimpsed. 



The Irregular Varl\ble Star, T Tauri. — The 

 annual report of the director of the Mount Wilson 

 Solar Observatory for 19 15 bears more resemblance 

 to a review of the world's work in astronomical physics 

 than the report of a single institution. The summary 

 contains seventy-eight important items. No. 61 states 

 that the irregular variable star, T. Tauri, is sur- 

 rounded by an extensive atmosphere 4" in diameter, 

 which shows the bright lines characteristic of Wolf- 

 Rayet stars. The spectrum of the star proper is about 

 F5. The magnitude of this remarkable object ranges 

 between 10-3 and 13-2. Notwithstanding the impres- 

 sive output of work it appears there is room for regret 

 — the 60-in. reflector remains the only instrument for 

 work on stars and nebulae, but it is offset by a cres- 

 cendo of hope — the lo-in. portrait lens telescope is 

 nearly ready, and the loo-in. reflector is expected to 

 ; be in working order by the end of 1916. 



A New Variable Star Having Nebulous Envelope. 



— ^An addition to this at present very limited group 

 I of extremely interesting objects is announced by Mr. 

 I R. T. A. Innes in Circular No. 33 of the Union Observa- 

 , ton.-. The star is —37° 8450 in the Southern Crown, 



and normally its magnitude is 87, but on two occasions 



■ last year, October 29 and November 24, it was con- 



■ siderably fainter (12-4 and 11-5 resf>ectively). The 

 nebulous envelop>e was also found to vary. The 6-88 

 magnitude star, —37° 8449, possesses a similar append- 

 age, and is so near to the above as to touch, thus 



, affording an excellent basis for comparison. It is 

 j tantalising to think that these stars actually come 

 above our horizon. 



NO. 2426, VOL. 97] 



