October 3, 1907] 



NA TURE 



581 



the instrument. An earth-connected metal scn-i;ii absorbed 

 the charge. 



Dr. Nodon's experiments also indicated that the 

 potential of the soil depends upon the variable electrical 

 state of the upper layers of the atmosphere, for when the 

 indicated potential of the solar charge received remained 

 constant, that of the soil was also constant, but with a 

 varying solar potential the terrestrial potential varied 

 several hundred volts per minute, attaining iti maximum 

 when the former ceased to manifest itself. This action is 

 much less marked at sea-level than at the altitude of the 

 summit of the Pic du Midi. It is suggested that the 

 rapid variations of the terrestrial potential may indicate 

 approaciiing tempests, storms, and even earthquakes, and 

 artual observations by Dr. Nodon tend to confirm this. 

 With this method improved, prognostications of atmo- 

 spheric and seismic troubles may become possible. On 

 August 21, between 8 p.m. and lo p.m., Dr. Nodon also 

 detected a positive induction produced by the full moon 

 analogous to the solar charge, and varying from one to 

 five volts per minute. 



Perth Cat.alogue of Standard Stars. — In " A Cata- 

 logue of 420 Standard Stars, mostly between 31° and 41° 

 South Declination, for the Equinox 19050, from Observ- 

 ations made at the Perth Observatory, Western .Australia," 

 Mr. W. Ernest Cooke, the Government astronomer of 

 Western Australia, appears to have done an excellent piece 

 of work, though one might wish that the details had been 

 given somewhat more fully. 



When some of the South American observatories failed 

 to fulfil their engagements with reference to the Inter- 

 national Photographic Chart of the Heavens, the gap was 

 to some extent bridged by the Perth Observatory under- 

 taking to observe the zone 32°-40° S. The catalogue 

 plates for this zone are now practically complete, but the 

 measurement of the star images and the necessary reduc- 

 tions are delayed by the want of a sufficient number of 

 known stars to furnish the plate constants. For this 

 reason it is proposed to observe some 10,000 stars, appro- 

 priately scattered throughout the zone, and for reasons 

 which are not explained the method of absolute determin- 

 ations has been abandoned in favour of zonal observations. 

 Unfortunately, .Auwors's catalogue, which has been 

 accepted as the basis of the system, does not contain a 

 sufficient number of standard stars, and it has been neces- 

 sary to choose others to act as secondary standards, and 

 to observe these repeatedly. The present catalogue gives 

 the places of 420 stars, which will be adopted as funda- 

 mental in the zone reductions. 



The number of observations of each star is usually ten, 

 and, judged by the probable error of a single observation, 

 the accuracv of the mean result should be sufficient for 

 the purpose. 



I7A.Y.V.4 MEETIXG OF THE IROX AXD STEEL 



IXSriTUTE. 

 "T^HE autumn meeting of the Iron and Steel Institute 

 was held in Vienna on September 23 and 24. under 

 the presidency of Sir Hugh Bell, and was largely attended, 

 there being about 450 members present. The proceedings 

 opened with addresses of welcome by the chairman of the 

 reception committee, by the Minister of .Agriculture and 

 Mines as representative of the Austrian Government, by 

 the Mayor of Vienna, and by the president of the .Austrian 

 Society of Engineers and .Architects, in the building of 

 which the meeting was held. The addresses of welcome, 

 which were delivered in German, having been translated 

 by the secretary, Mr. Bennett H. Brough, the president. 

 Sir Hugh Bell, responded in an eloquent German speech, 

 and incidentally announced that the .Archduke Frederick 

 of .Austria, who had acted as patron of the reception com- 

 mittee, had accepted honorary membership of the institute. 

 The technical business then began. 



Mr. W. Kestranek read the first paper. It recorded 

 the progress made in the .Austrian iron industry during 

 the twenty-five years that have elapsed since the institute 

 last met in Vienna. In 1882 Austria-Hungary produced 

 600,000 tons of pig iron, and the annual output has now 

 risen to i.qoo.ooo tons. The countrv suffers from a 

 scarcity of coking coal. It has nevertheless been able to 



NO, 1979, VOL. 76] 



maintain its position among the iron-producing countries 

 of the world. 



In the second paper read, Prof. H. Bauernian described 

 the Erzberg of Eisenerz, the largest of the series of 

 mineral deposits associated with the PaliEOzoic rocks of the 

 eastern .Alps. The raw ore averages 38-73 per cent, of 

 iron, and the calcined ore 5068 per cent. The ore is 

 obtained by quarrying, the entire face of the deposit being 

 laid out in a scries of steps or terraces, fifty-eight in all, 

 varying in height from 33 feet to 43 feet, giving a total 

 depth of working faces of about 2000 feet. The present 

 annual output is about 1,600,000 tons. The mining of 

 iron ore on the Erzberg has been carried on from very 

 earlv times. Traditionally, the workings date back to the 

 eighth century, but there arc no authentic records older 

 than A.D. 931. 



.A paper on steel and meteoric iron was read by Prof. 

 F. Berwerth (V'ienna). The paper was prepared by way 

 of introduction to the meteorite collection of the Imperial 

 Natural History .Museum, where opportunities are afforded 

 for the study of meteoritic iron masses under conditions 

 unequalled elsewhere. Meteoritic falls from 615 different 

 localities are represented in the collection by 2075 speci- 

 mens, the total weight of which is 35 tons. Of these, 

 232 falls are iron meteorites, weighing together more than 

 2j tons. The author's descriptions show that meteoritic 

 iron and steelworks' steels are results of essentially similar 

 chemical and physical causes. 



Prof. J. von Ehrenwerth (I.eoben) read a useful paper 

 on the determination of the total quantity of blast-furnace 

 gas for a given make of pig iron. The method proposed 

 should prove of great value in view of the increasing 

 importance of the waste gases as an economic factor in 

 iron smelting, more particularly since their successful 

 application in driving gas-engine? makes it necessary that 

 closer control should be exercised in their disposal. 



At the present time there is a constantly increasing 

 number of cases in which industrial practice is profiting 

 by the application of the laws of modern physical 

 chemistry. Some examples of conclusions dealing with 

 the metallurgy of iron which may be arrived at in this 

 way were given in a lengthy paper contributed by Baron 

 H. von Juptner (Vienna). He dealt more particularly with 

 the laws of chemical equilibrium as applied to metal- 

 lurgical chemical processes. 



In a paper read before the institute last May, Mr. 

 C. E. Stromever (Manchester) mentioned several failures 

 of steel plates and structures, which appeared to indicate 

 that certain qualities of mild steel might have the property 

 of changing their nature with age. In a supplementary 

 paper he gave the results of further experiments. They 

 have not revealed a test which will discriminate between 

 trustworthv and treacherous qualities of steel, but they 

 have nevertheless established the fact that mild steel does 

 possess ageing properties, and that certain practices which 

 are still fairly common amongst engineers are not free 

 from dangerous possibilities. 



Four papers were read on the subject of hardening 

 steel. Mr. C. O. Bannister (London) and Mr. W. J. 

 Lambert (Woolwich) dealt with the case-hardening of mild 

 steel, giving the results of some observations on the micro- 

 structure of cemented bars, on the depth of hardness, and 

 on the carbon contents. The results do not throw much 

 light on the manner in which the carbon penetrates the 

 metal, but the authors consider that the solid solution 

 theorv is capable of offering a satisfactory explanation. 

 Mr. G. Shaw Scott (Birmingham) also contributed a paper 

 on case-hardening. He considered that nitrogen in some 

 form is necessary for the practical performance of case- 

 hardening, and suggested that ammonia, whilst being the 

 prime agent in any change, may lead to the formation 

 of cvanogen, which acts as a carrier of carbon to the 

 metal to be carburised. Nitrogen, he concluded, should 

 be added to the list of elements which cause iron to take 

 or retain the 7 form ; and since 7 iron combines more 

 readilv with carbon than does a iron, the action of nitrogen 

 on the iron would appear to be sufficient to explain its 

 beneficial effect during the early stages of the process of 

 case-hardening. Throughout the research burnt leather, 

 which is in general use in trade circles in England, was 

 1 employed as the standard case-hardening material. 



