NOVEAIBER 14, 1912] 



NATURE 



0^1 



an ingot have solidified, and even that information is 

 of some importance. 



Sir Robert Hadfield's method for producing sound 

 in.yots consists in producing solid "piping" steel, and 

 then arranging matters in such a way that the ten- 

 dency to form a pipe is neutralised by a full supply 

 of hot liquid steel from above. This is attained by 

 attaching to the top of the ingot-mould a "feeding 

 head" lined with sand; this practically constitutes an 

 upward continuation of the ingot-mould, and when 

 the mould is filled the steel is allowed to rise to some 

 distance into this attachment. The steel in this 

 feeding-head is, however, to be kept molten until the 

 solidification of the ingot proper is completed, and 

 this is attained in Hadfield's process by covering the 

 surface of the steel first with a thin layer of cupola 

 slag', which serves to protect the metal against both 

 thermal loss and chemical contamination, and then 

 with a layer of charcoal, which is brought into a 

 lively incandescence by the action of a blast of 

 compressed air. The author gives numerous examples 

 and full particulars of results attained in this way, 

 and although in the discussion on this subject doubts 

 were expressed as to the practicabilit}- of the process, 

 and to some extent as to its novelty, its efficacy was 

 admitted. 



Another method intended to serve the same purpose 

 of producing sound ingots was described by Dr. 

 Hans Goldschmidt, who claims for it favourable 

 results with thousands of actual ingots. This method 

 consists in the introduction into the central, fluid part 

 of a partially solidified ingot of a cartridge of 

 " thermit." The amount of thermit used is small — 

 about one pound per ton of steel — so that the heat 

 generated is strictly local and quite negligible. The 

 introduction of the thermit cartridge, which consists 

 of an iron canister pushed down with an iron rod, 

 results in a boiling or frothing up, followed by a 

 settling of the steel in the mould, this shrinkage being 

 made good by the addition of a further small amount 

 of molten steel from the ladle. The author suggests 

 that the thermit reaction taking place near the bottom 

 of the solidifying ingot results in the removal of gas 

 and of entangled slag, but this point of view was not 

 at all appreciated in the discussion ; in fact, Dr. Gold- 

 schmidt's proposals were scarcely taken seriously. Thus 

 .Stead suggested that the addition of a sm.nl'. amount 

 of aluminium to the steel in the ladle would produce 

 the same effects — a suggestion strongly repudiated 

 bv Goldschmidt. In view of the large amount of 

 practical evidence brought forward in the paper, this 

 treatment was a little surprising. 



In the course of the discussion on these papers, Dr. 

 T. E. Stead described a method introduced by Talbot 

 for the production of sound ingots. In this process 

 the ingots are passed through the "cogging mill" 

 before their interior portions have become solid, and 

 in this wav the wider end of the ingot is compressed 

 and the liquid steel is forced to fill up any shrinkage 

 cavities which might be in course of formation. In 

 principle this process is similar to the Harmet method 

 of compressing steel ingots during their solidification, 

 but if it proves to be practicable to handle and lightly 

 roll ingots consisting of molten steel with a mere 

 external crust of solidified metal, the method may 

 justifv the enthusiastic predictions of its sponsor. 

 Talbot's own account of his procedure, with the 

 statistical data demanded by Hadfield, will, however, 

 be awaited with interest. 



.\mong the more scientific papers which were taken 

 as read at the meeting, the most interesting from the 

 general point of view is that of Benedicks on allotropy 

 in general and that of iron in particular. In this paper 

 the author begins bv raising the question whether 



NO. 2246, VOL. 90] 



allotropic or polymorphic changes are necessarily 

 sudden, i.e. whether they must occur at one definite 

 temperature or whether they may in certain cases 

 occur continuously over a certain range of tempera- 

 tures. He arrives at the latter conclusion, and ex- 

 presses it by saying that all degrees of mutual solu- 

 bility of the two allotropic modifications in one another 

 are theoretically possible. In the case of a consider- 

 able mutual solubility an allotropic "transformation 

 point " would cease to exist, but where the solubility 

 is one-sided, the modification ii. being slightly 

 soluble in the modification i., but not vice versa, there 

 would be a gradual change upon one side of the trans- 

 formation point with a large sudden change at that 

 point itself. By means of accurate dilatometric 

 measurements on silver iodide. Benedicks shows that 

 the transformation of this body is of the type just 

 indicated, the curve of dilatation giving the precise 

 shape required on the assumption that the high-tem- 

 perature modification is to some extent soluble in the 

 low-temperature modification at temperatures just 

 below the transition point, the solubility decreasing 

 with falling temperature. This accounts for the nega- 

 tive dilatation at room temperatures. 



When this view is applied to the case of iron, the 

 author considers that the critical point at or near 

 890° C. is a definite allotropic change-point, but he 

 does not regard beta iron as a separate allotropic form, 

 explaining the existence of the beta range on the basis 

 that gamma iron is soluble in alpha iron to an extent 

 which increases with the temperature until the critical 

 point is reached. Benedicks considers that this view- 

 would greatly simplify the metallography of iron, 

 since it would reconcile the three theories now accepted 

 as most probable regarding the nature of martensite. 

 This interesting paper would undoubtedly have given 

 rise to one of those spirited discussions for which this 

 particular subject is noted, and it is a pity that so 

 important a communication should have been passed 

 over ; it may be hoped, however, that it will receive 

 full attention in the discussion by correspondence 

 which forms so interesting a feature of the Journal of 

 the institute. 



HEREDITY AND EUGENICS. 



THE third and last number of The Mendel Journal 

 contains an interesting article on the alterna- 

 tive heredity of mental traits, by Dr. Frederick 

 Adams Woods, of the Massachusetts Institute of 

 Technology. Dr. Woods's previous studies of heredity 

 as exemplified in Royal families attracted a great deal 

 of attention, and the present short paper based on the 

 same class of material is well worthy of study. He 

 advances the argument that the contrasts shown in 

 the characters of children born of the same parents 

 and brought up in the same environment are evidence 

 for, and not against, the inheritance of mental traits. 

 Those who would insist, as many do, that psychical 

 characters are wholly the expression of the environ- 

 ment will find these contrasts very difficult to explain, 

 but to their opponents who attribute the preponderating 

 influence to heredity they present no difficulties, since 

 the possibility of alternative inheritance has never been 

 disputed. Among the other contents of the number is 

 an article on primitive eugenics, by Mr. E. Torday, 

 in which the eugenical value of the customs of certain 

 central African "tribes is pointed out and their good 

 effects described. 



The American Eugenics Record Office was founded 

 in 1910, and is now well established in a career of 

 useful activity. Among its latest publications is Prof. 

 C. B. Davenport's "Trait Book" (Bulletin No. 6). 



