462 



NA TURE 



September 10, 1903 



direction in a similar manner to the ordinary rocket, and 

 in the experiments performed by Messrs. NichoUs and Hull 

 this " reaction " pressure would be about ten times as great 

 as the " radiation " pressure. This research has ex- 

 perimentally illustrated the repulsion, and has shown that 

 a part of it at least is probably due to the " radiation " 

 pressure ; it now remains to determine more definitely the 

 relative effect of each of the possible causes. 



A Catalogue of 1520 Bright Stars. — As the " Revised 

 Harvard Photometry," which will contain details of about 

 nine thousand stars of magnitude 6-5 and brighter, is not 

 yet ready, the Harvard College Observatory has published 

 a smaller catalogue, which only contains 1520 stars, and 

 does not give the detailed information which will be con- 

 tained in the larger volume. 



The catalogue gives, in tabular form, the H.P. number, 

 the constellation name, the R.A. and declination, the 

 magnitude and the type of spectrum for each star, and a 

 comprehensive set of " remarks " describes the peculiarities 

 appertaining to various stars included in the list. 



A large edition of the catalogue has been prepared, and 

 anyone interested may obtain a copy on applying to the 

 director. 



IRON AND STEEL INSTITUTE. 



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

 held in the Town Hall, Barrow-in-Furness, on 

 September i, 2, and 3, with Mr. Andrew Carnegie,' the 

 president, in the chair, and was very largely attended. 

 After an eloquent address of welcome from the Mayor, Mr. 

 Carnegie delivered a short presidential address, in which 

 he traced the progress made in the metallurgy of iron and 

 steel since the Institute's last visit to Barrow twenty-nine 

 years ago. After various business announcements had been 

 made by the secretary, Mr. Bennett H. Brough, the reading 

 and discussion of the thirteen papers on the programme 

 began. The first read was that by Mr. R. A. Hadfield on 

 the alloys of iron and tungsten. This formed a monograph 

 of sixty-eight closely printed pages. It contains historical 

 details regarding the ores of tungsten, the metal and its 

 alloys, and a large amount of physical data. It concludes 

 with a carefully compiled bibliography of the subject, show- 

 ing that a large amount of attention has been devoted to 

 studies of this interesting metal and its employment in the 

 manufacture of steel. Osmond, by his cooling curves, has 

 brought out several peculiar points in the thermal behaviour 

 of this steel, and Barrett has discovered that tungsten 

 affects the conductivity of iron less than any other added 

 element. Though tungsten-iron alloys will have an im- 

 portant future, there is no doubt that their use is not likely 

 to be on the same large scale as some Of the other special 

 steels now produced. In the discussion some interesting 

 details were added by Mr. F. W. Harbord and by Mr. J. E. 

 Stead. 



This paper was followed by a series of memoirs dealing 

 with the heat treatment of steel. These were discussed 

 together. 



The paper read by Mr. J. E. Stead and Mr. Arthur W. 

 Richards on the restoration of dangerously crystalline steel 

 by heat treatment established facts of far-reaching import- 

 ance. The microscope shows that heating at high tempera- 

 tures causes a great development in the size of the crystal- 

 line grains, and reheating to about 870° restores the original 

 or a better structure. If all structural steels in their normal 

 rolled or forged condition are good, they can be readily 

 deteriorated in quality by heating to a temperature a little 

 above that to which steel is most commonly heated previous 

 to rolling or forging. Steel made brittle by such heating, 

 and dangerously brittle by heating at considerably higher 

 temperatures, can be completely restored to the best possible 

 condition without forging down to a smaller size or by re- 

 melting. Not only are the original good qualities of 

 normally rolled steel, after making brittle, restored by the 

 exceedingly simple treatment of heating to about 900° C. 

 for a very short time, but such steel is made considerably 

 better than it was. That brittle " soft steel " can be re- 

 stored by reheating is well known, but that carbon steels 

 c^n be actually made much superior to the original properly 



NO. 1767, VOL. 68] 



forged metal by reheating to 870° and cooling in air is a 

 discovery. It is urged that in every large forge and smith's 

 shop Le Chatelier pyrometers should be introduced, together 

 with suitable furnaces for reheating the forgings. 



Mr. J. E. Stead and Mr. Arthur VV. Richards next read 

 a remarkable paper on sorbitic steel rails. The term 

 sorbitic is used for a transition condition of the carbide 

 intermediate between the states in which it exists in 

 hardened and annealed steels. The chief point of interest 

 in the authors' work is the simple method employed for 

 ptoducing sorbite in steel. The usual custom has been to 

 reheat and oil-harden, or to quench completely in water and 

 reheat to dull redness. They avoid reheating, and quench 

 the heads of the rails, and allow the residual heat in the 

 rails to do the tempering. The results of the later experi- 

 ments show clearly enough that by partially quenching the 

 heads and allowing the rails to temper themselves, although 

 the elongation is decreased, the contraction of area remains 

 practically the same. A normal rail of 37 tons tenacity 

 when made sorbitic is increased in strength to 45 tons with- 

 out diminution of the contraction of area. A normal rail 

 with 362 tons tenacity is increased to 49 tons with a slight 

 increase in the contraction of area. In other cases the 

 tenacity is increased from 43 to 50 tons with a slight diminu- 

 tion in the contraction of the area. Pieces of the rail cut 

 from the area of maximum sorbite on being tested by re- 

 peated reversals of strain showed greater toughness and 

 endurance than the normal material. The wear is very 

 greatly in favour of the sorbitic material, as would naturally 

 be expected, and it is believed that, by treating the rails 

 in the simple manner described, their life will be increased 

 from 25 to 50 per cent. The results obtained should lead 

 metallurgists to aim at replacing pearlite by sorbite in all 

 structural steels that have to be subjected to friction, per- 

 cussion, or vibration when in use. 



A paper on the heat treatment of steel rails high in 

 manganese was contributed by Mr. J. S. Lloyd (South 

 Russia). Steels containing more than i per cent, of 

 manganese have not hitherto been fully studied, and a re- 

 search carried out in Russia by the author shows that, at 

 the ordinary normal heat suitable for rolling ingots, steel 

 containing 0-46 per cent, of carbon and 1-33 per cent, of 

 manganese is made exceedingly brittle if it is not further 

 treated, but is allowed to cool on the mill floor. Slowly 

 cooling in the furnace after heating for eighteen hours at 

 950° makes the material about twice as ductile as it was 

 in the original rail, but the tenacity is considerably reduced. 

 The heating to the rolling temperature causes an enormous 

 development in the size of the crystals, but these are broken 

 up and become about one-eighth of the dimensions by heat- 

 ing to 950° C. and slowly cooling afterwards, and the 

 structure so obtained is twice as fine as it was in the normal 

 rail. 



Some further experiments on the diffusion of sulphides 

 through steel were described by Prof. E. D. Campbell, of 

 the University of Michigan. They appear to sustain the con- 

 clusions drawn from his work — that iron is permeable by 

 sulphides when heated above 1200° C, and that the sulphur 

 content of the iron is not necessarily increased by the passage 

 of the sulphide through it. In fact, in a slightly oxidising 

 atmosphere the sulphur content of the steel may be even 

 less after the diffusion than it was before. The author is 

 not prepared at present, from the experimental data at 

 hand, to give a positive explanation of the manner in which 

 sulphides permeate or diffuse through iron. The most 

 plausible hypothesis would seem to be that the sulphides 

 originally present in the iron fill more or less completely 

 the interstitial spaces between the crystals of iron ; that 

 above 1200° these sulphides are very fluid, and may be 

 drawn out of the steel by capillary action of some absorbent 

 such as asbestos, and their place taken by some other 

 sulphides, provided these latter are sufficiently mobile to 

 find their way into the extremely minute spaces between 

 the steel crystals. If the sulphide replacing the original 

 sulphide contain less sulphur than the latter, or if absorp- 

 tion by the asbestos continued after the sulphides had 

 ceased to enter the iron from within, the diminished per- 

 centage of sulphur in the steel at the hot end would be 

 readily accounted for. 



The paper by Prof. A. Stansfield on the overheating and 

 burning of steel was a report on work carried out by him 



