October 17, 1912] 



NATURE 



degree below a Serpentis. When seen on a dark sky 

 it presented an extensive coma witli a large bright 

 nucleus and a tail at least half a degree in length. 

 Mr. Franks also reports that it was nearly a degree 

 north of its predicted position on October ii, and 

 that the difference is increasing, but it seems probable 

 that he was using the earlier ephemeris published by 

 Dr. Ebell, and not the later one from which we gave 

 an extract last week. The following is a continuation 

 of the corrected ephemeris : — 



According to this ephemeris, the magnitude should 

 now be 6'6. and decreasing slowly, but, as Mr. Franks 

 remarks, the comet is exceeding expectations, and, 

 with its indications of abnormal brightening, may 

 well renav careful observation, especiallv in the form 

 of a close series of photographs, bv those who are 

 favourably situated; on October 21 the comet will be 

 about one-third of a degree east of 7 Serpentis. 



The Recent Total Eclipse of the Sun. — It is with 

 much regret that we learn from Greenwich that all 

 attempts to make observations of the recent total 

 eclipse of the sun were frustrated by the heavy rain 

 which prevailed in the eclipse region of Brazil on 

 eclipse day, October 10. The Greenwich observers, 

 Messrs. Eddington and Davidson, were located at 

 Alfenas, an elevated village some 185 miles north of 

 Santos, where there were also eclipse parties from 

 France, Germany, Brazil, and other countries. The 

 Brazilian officials rendered all the assistance they 

 could, and the Government voted a sum of 5000Z. for 

 the reception of the visiting astronomers at Rio. 

 According to a characteristicallv interesting letter 

 from Mr. J. J. Atkinson, which appeared in The 

 Morning Post on October 8, the Greenwich equipment 

 weighed about three tons, and had to be transported 

 from Rio to the terminus of the State railway, a dis- 

 tance of about 150 miles towards the mountains ; 

 owing to the sharp incline the latter part of the track 

 has to be worked on the cog system. Mr. Atkinson, 

 who accompanied the Greenwich observers as a volun- 

 teer, also recites some interesting reminiscences of 

 his previous eclipse experiences. 



The Constant of Aberration. — In No. 15, 

 vol. xxvii., of The Astronomical Journal, Prof. C. L. 

 Doolittle gives the result of twenty-two determinations 

 of the aberration constant derived from thirty-two 

 years' latitude work at the Sayre and Flower Observa- 

 tories. The observations were made at two different 

 places, with what are practically four different in- 

 struments, only the observer remaining the same, and 

 the mean probable error is less than o'oi". Taking 

 the weighted mean of all the observations. Prof. Doo- 

 little finds for the constant the value 2o'525"+o'oo43", 

 and the corresponding value for the solar parallax is 



THE AUTUMN MEETING OF THE 

 INSTITUTE OF METALS. 

 T^HE papers presented at the autumn meeting of 

 -■■ the Institute of Metals, which took place at the 

 Institution of Electrical Engineers on September 25 

 ancl 26, may be divided into two groups according as 

 their interest lies principally on the practical or on 

 the scientific side. 



Among the " practical " group two papers dealing 

 NO. 2242, VOL. 90] 



with the joining of non-ferrous metals and allovs may 

 be mentioned. In these Prof. Carnevali, of 'Turin, 

 and A. E. Tucker, of Birmingham, discuss the ques- 

 tion of autogenous welding, although the latter paper 

 also deals in an interesting if somewhat scrappy 

 manner with many other processes, such as soldering 

 and brazing, &-c. In view of the great extension of 

 autogenous welding by means of oxygen and acetylene, 

 the question how far the results of this process can 

 be trusted is an important one. Tucker appears to 

 regard a weld as satisfactory if it is found on testing 

 it to destruction that the fracture occurs away from 

 the weld itself. As a matter of fact, however, the 

 weakest portion of a welded joint, as Carnevali points 

 out, is not the weld itself, but the region of injured 

 metal on either side of it. According to this author 

 the strength of welds in copper and its principal alloys 

 cannot be depended upon, and this conclusion agrees 

 with the views on autogenous welds in iron and steel 

 recently expressed by Fremont and others. In regard 

 to pure aluminium, however, Carnevali finds the 

 method to give satisfactory results, but the efficiency 

 of a weld is much reduced as soon as it is applied 

 to one of the stronger light alloys of aluminium. 

 Broadly speaking, these papers lead one to view the 

 rapid development of autogenous welding practice 

 with some susp.icion. 



Still on the " practical " side were a number of 

 papers dealing with impurities in copper and copper 

 alloys. An interesting and suggestive paper by E. F. 

 Law dealt with oxygen and oxides as deleterious 

 impurities in alloys. This author took the view that 

 progress in non-ferrous alloys was largely a question 

 of the better elimination of oxides, and this view was 

 strongly supported in the discussion by Rosenhain. 

 The paper by Prof. Turner, however, emphasised the 

 existing difficulties in the way of analytical determina- 

 tion of oxygen in brass, and an appeal was made to 

 chemists to devise a satisfactory method for this pur- 

 pose. F. Johnson dealt with the effect of impurities, 

 chiefly antimony, on the properties of tough-pitch 

 copper, and here again discussion centred round the 

 part played by oxygen. The lenient view as to the 

 deleterious effects of antimony put forward by the 

 author was, however, strongly opposed by all those 

 who have to deal with copper on the large scale. 

 Other papers of a " practical " character dealt with 

 high-temperature tensile tests on copper and its alloys, 

 and with the annealing of coinage alloys, and both 

 these papers were vigorously criticised in the discus- 

 sion on the ground of the experimental methods em- 

 ployed by the authors. 



The " scientific " papers were not so numerous, but 

 of speciar interest. Prof. H. C. H. Carpenter con- 

 tributed two papers dealing in further minute detail 

 with the inversion which he has discovered in a 

 certain range of copper-zinc alloys (brass) at a tem- 

 perature of 470° C. In one of these papers the author 

 deals with the effect of impurities on this inversion 

 and finds that any addition of a third metal to these 

 alloys tends to facilitate rather than to inhibit the 

 transformation in question ; since the change renders 

 the metal weak and more brittle, it is evident that 

 the use of the purest copper and zinc is desirable in 

 the manufacture of those varieties of brass containing 

 the constituent. 



In a very short note Dr. G. T. Beilby, F.R.S., 

 discusses the phenomena of the solidification of metals 

 from the liquid state in reference to the "foam cell" 

 theory of Quincke. In his May lecture to the insti- 

 tute, Dr. Bielby had suggested the importance of a 

 full experimental investigation of the views put for- 

 ward by Quincke, and the present note is intended to 



