No. 1072, Vol. 42] 



NA TURE 



69 



Scotland, and others, gave the valuable infonnation drawn from 

 the practical experience they had gained in the alloying of iron 

 with aluminium on a large scale. We will, however, take the 

 papers so far as space will permit, in the order in which they 

 were read. 



Mr. Head's paper was read at the Paris meeting of the Insti- 

 tute, held last autumn, but was not then di-cussed. The author 

 first points out that, in 1817, the Rev. Robert Stirling and his 

 brother James Stirling applied the regenerative principle to air- 

 engines, and that both they and J. Slater, in 1837, and R. 

 Laming in 1847, foresaw the possibility of its application to 

 metallurgical operations. The new Siemens furnace, which was 

 the subject of the paper, was described and illustrated by wall- 

 diagrams, without reproducing which it is not possible to make 

 the arrangement clear. The chief point is that the waste gases 

 are reconverted into combustible gases by being taken partly 

 through an air-regenerator, and partly under the grate of the 

 producer, so that they distil the hydrocarbons from the coal ; in 

 fact, the gas-producer utilizes the heat formerly deposited in the 

 air regenerators. A steam jet is used for starting the action. 

 This new form of regenerative gas-furnace has been applied to 

 heating and welding of iron. It is to be used for puddling, 

 for copper and steel melting. It is claimed that it effects a 

 ing in fuel of about two- thirds the weight, a reduction in the 

 ht of iron equal to 5 per cent., and a saving in labour and 

 irs. Figures were quoted supporting these claims. 

 rof. Akerman's paper was a discussion on the theory of com- 

 ion raised by the process. The subject is one of consider- 

 le interest, and is well put forward by the author. His con- 

 ions are of considerable interest from a philosophical point 

 of view, but are to a great extent robbed of their importance 

 from an operative standpoint, from the uncertainty existing upon 

 the specific heat of gases at high temperatures ; which is only 

 one more fact emphasizing the want of a proved and trustworthy 

 pyrometer. 



A brief discussion followed, in which Sir Lowthian Bell took 

 the chief part. 



M. Osmond's paper was one of those which must be the 

 despair of the writers of brief notices such as this. It consisted 

 of 33 pages, giving results of experiments made to ascertain the 

 effects of varying temperature on different alloys of iron. In 

 the presence of such a mass of matter as this we can only 

 refer our readers to the Transactions of the Institute, where 

 they will find the facts detailed and the diagrams by which they 

 were illustrated fully set forth. We will content ourselves with 

 simply stating that the " critical points " are points of arrestation 

 in the cooling of iron and steel. It is interesting to notice the 

 effect of various alloys on this phenomenon. Perhaps, to those 

 members who were not previously acquainted with the instru- 

 ment, the description of the thermo-electric pyrometer of Le 

 Chatelier was not the least interesting part of the paper. A 

 valuable bibliography is given in an appendix. In the discussion 

 Mr. Wrightson gave some particulars of experiments he had 

 made to ascertain the change of volume of iron at different 

 temperatures, which he did by plunging an iron ball into liquid 

 iron. The ball would at first sink, but rise as it acquired heat, 

 and indications were thus obtained, which appeared to correspond 

 with the "critical points " of the author. Mr. Hadfield also 

 made some interesting remarks on the state of carbon in iron. 



Prof Roberts- Austen's paper followed. The Professor is not, 

 of course, the first to carburize iron by means of the diamond ; 

 indeed, it has been a somewhat favourite experiment, with which 

 the name of more than one eminent physicist in times past has 

 been associated. But Prof. Roberts- Austen is, we believe, the 

 first to perform the operation hi vacuo, the iion itself being 

 previously heated in vacuo to deprive it of its occluded 

 gas. The author of the paper refers to the experiments of 

 Tiempel, who heated diamond and iron in an atmosphere of 

 nitrogen perfectly free from oxygen, and points out that his, the 

 author's, experiments are interesting from the assertions made 

 by a certain school of chemists that no two elements can react 

 on each other unless a third be present. "It would appear, 

 however," Prof Roberts- Austen says, "that a mere 'trace' of 

 such additional element is sufficient to insure combination ; for, 

 in the experiments I have described, carbon and iron in their 

 purest obtainable forms were used, and the only additional 

 matter which could have been present was the trace of occluded 

 gas which the iron may possibly have retained." The author 

 is satisfied that combination does not take place until a full red 

 heat is reached. 



Dr. Ball's paper dealt with the changes in the magnetic 

 capacity and tensile strength of steel which occur at definite 

 temperatures, and showed how these changes may be made 

 evident when the metal is rapidly cooled in water or in oil. 

 Two samples of steel, one basic Bessemer and the other acid 

 open-hearth, were submitted. Analysis showed that all the 

 elements for which tests are usually made were almost identical, 

 except manganese, of which the percentages were o'284 for 

 Bessemer, and 0*546 for open-hearth. The results are plotted 

 on three sets of diagram?, one diagram in each set showing the 

 results obtained with tests hardened, from varying temperatures, 

 in water, in oil, and annealed respectively ; the sets of diagrams 

 refer to unstrained bars, the same bars strained to the yield 

 point, and the same bars strained almost to the breaking point. 

 These last two papers were discussed together. 



Mr. Garrison's paper was read at the Paris meeting of Sept- 

 ember last, but not then discussed. It describes an elliptical 

 converter in which the luyires are so arranged that they blow 

 air at the surface of the metal in a manner which causes a rotary 

 motion of the bath, combustion taking place at the surface. 

 The device is not altogether new, as surface blowing was sug- 

 gested, and, indeed, patented, by Sir Henry Bessemer in the 

 early days of the Bessemer process. 



Mr. Keep's paper on aluminium, in carburetted iron, was the 

 first taken on the Thursday morning. In it the results of 

 certain tests were given, the details being set forth in graphic 

 form. The points noted were strength to resist both weight and 

 impact, deflection, set, elasticity for stresses applied, shrinkage 

 for cast metals, hardness, and rigidity. This paper must be 

 read with others that have been brought forward by the author, 

 whose work in connection with the subject is well known. As 

 a general result the tests go to show that the effect of a proper 

 quantity of aluminium on commercially pure iron is to produce a 

 material which is soft, easily bent, and flows readily. Aluminium 

 diminishes deflection by decreasing the set and elasticity. 

 Rigidity is also increased, the grain is closer and more uniform ; 

 in short, the author claims that by aluminium the metal is 

 improved in every way when considered as a structural material. 



In the discussion which followed the reading of the paper, 

 Mr. James Riley, the manager of the Steel Company of Scot- 

 land, said that he had tried the effect of aluminium in steel on a 

 large scale, but had been disappointed in the results. There 

 were advantages, but these were so slight as to be insufficient to 

 pay for the additional expense of one to two pounds a ton. 

 Fluidity was gained, tensile strength was very slightly increased, 

 the elastic limit was raised considerably, and ductility was in- 

 creased. If aluminium could be reduced sufficiently in price it 

 would be good to use it, but Mr. Riley had not considered the 

 game worth the candle, and had ceased to use it a year ago. He 

 had, however, been induced lately; by being told of the wonder- 

 ful results obtained, to make further experiments, but his present 

 frame of mind was not to use aluminium excepting for very fine 

 thin castings. Mr. Spencer, of Newburn, another large steel- 

 maker who has achieved great success in certain special branches 

 of manufacture, endorsed what Mr. Riley had said. Mr. Allen 

 pointed out that there might be traces of aluminium in pig-iron 

 without its being discovered, as chemists only tried, as a rule, for 

 the usual alloys. It was also important to remember that 

 although aluminium might be put into the pot it did not neces- 

 sarily appear in the product, as it might be removed by chemical 

 reaction during the process. The latter point was supported by 

 Dr. E. Riley and Mr. Stead. 



Mr. Galbraith's two contributions were next read and discussed, 

 but do not call for any special mention. Finally, Mr. A. Rollet's 

 paper was read, in which his process of obtaining purified metal 

 for castings waj described. The process was illustrated by dia- 

 grams, and may be said briefly to consist of eliminating from pig- 

 iron, to be used for the manufacture of particular qualities of steel, 

 sulphur, phosphorus, and silicon. The pig is placed in a special 

 cupola, and is maintained at a very high temperature under a 

 dopble action, slightly reducing and slightly oxidizing, in the 

 presence of a slag obtained by admixtures of limestone and 

 lime, iron ores, and fluor-spar. By the arrangement of the cupola 

 the meial is separated from the slag as soon as they are removed 

 from the action of the blast in tapping. In this way the phos- 

 phorus already eliminated is prevented from going back into 

 the metal, and too great a recarburization is also avoided. The 

 elimination of sulphur is complete up to 99 per cent, and even 

 more ; that of phosphorus amounts to 80 or 85 per cent., or even 

 90 per cent, and more. 



