October 8, 19 14] 



NATURE 



153 



Carboniferous times (p. 95), and that the Karroo 

 strata of Katanga and Rhodesia were formed in the 

 lowered areas. The "graben" of the great lake 

 region is of much younger age. H. S. Harger, in 

 his presidential address (vol. xvi., p. xxii.), points 

 out that the Drakensberg lavas are of Jurassic age, 

 and probably extended at one time right across 

 the Free State. He is concerned with the immense 

 amount of subsequent denudation, but does not 

 explain how the "vast peneplain" over the entire 

 Karroo (p. xxviii.) came about, if the surface remained 

 high above sea-level. A great inland lake might, of 

 course, supply a base-level. He contrasts the periods 

 of great river-action with those of subsequent desic- 

 cation, and gives striking illustrations of denudation 

 by sand-storms in German South-West Africa. May 

 we ask that this energetic society should consider those 

 members who cannot promptly bind the Transactions? 

 They have a way of falling to pieces when one cuts the 

 pages which renders them very liable to denudation. 



F. Oswald, well known for his researches in 

 Armenia, has described "The Miocene Beds of the 

 Victoria Nyanza and the Geology of the Country be- 

 tween the Lake and the Kisii Highlands " (Quart. 

 Journ. Geol. Soc. London, vol. Ixx., 1914, p. 128). 

 His journey through a fly-infested region was under- 

 taken to collect vertebrate remains from lacustrine 

 strata, which underlie extensive flows of nepheline- 

 basalt. C. ^^^ Andrews describes the mammalia, in- 

 cluding Dinotherium and two anthracotheres, and R. 

 Bullen Newton shows that the associated freshwater 

 mollusca represent existing species. The mammalia, 

 however, assign the deposits, which were formed prob- 

 ably in a delta, to the Burdigalian epoch, and the 

 history of the Victoria Nyanza is thus carried back 

 into the middle of Cainozoic time. 



R. B. Newton enters the African field in another 

 paper (Records of the Albany Museum, Grahamstown, 

 vol. ii., 1913, p. 315), in which he shows that the 

 extensive Alexandria formation of the Cape Province 

 is of Cainozoic age, and distinct from the Cretaceous 

 strata occurring near East London. Several new 

 molluscan species are represented in a beautiful series 

 of photographic plates. 



A. E. V. Zealley ("Zinc and Lead Deposits of 

 Broken Hill, N. Rhodesia," South African Journ. 

 Sci., vol. viii., 1912, p. 396), remarks that the phos- 

 phates in this area, including the beautiful deposits 

 of hopeite, are connected with the decomposition of a 

 bone-breccia, and that vanadinite arises in connection 

 with the zinc and lead phosphates in a way which sug- 

 gests that vanadium occurs also in the bones. 



THE INSTITUTE OF METALS. 



J N the study of the constitution of alloys, as well as 

 -*■ in the practical and commercial use of both pure 

 metals and alloys, that form of heat treatment known 

 as annealing plays an important part, and a complete 

 knowledge of the effects of various temperatures and 

 conditions of annealing is of vital importance. This 

 statement is not invalidated by the fact that many of 

 our large metal works conduct their annealing opera- 

 tions in the most crude and haphazard way, a state 

 of affairs which is, happily, becoming a thing of the 

 past. In this connection it is interesting to note that 

 one-third of the papers read at the recent meeting of 

 the Institute of Metals deal, to a greater or less 

 extent, with this important subject. J. Phelps shows 

 that the presence of hydrogen in the atmosphere sur- 

 rounding silver which is being annealed, increases the 

 temperature required to obtain complete softness in 

 thirty minutes, from below 150° C. to about 300° C. 

 F. Johnson emphasises the necessity of annealing 

 NO. 2345, VOL. 94] 



Admiralty brass castings to a temperature of about 

 700° C. Bengough and Hanson show that copper 

 tested to destruction in an oxidising atmosphere has 

 an elongation four times as great, and a maximum 

 stress one-third as great, as that obtained when the 

 test is carried out in a neutral atmosphere such as 

 carbon dioxide. 



Bengough and Hanson's paper also contains much 

 interesting information as to the tensile properties of 

 copper at high temperatures. They show that this 

 metal fits in very well, on the whole, with Rosenhain's 

 amorphous theory, the fracture changing from a duc- 

 tile, crystalline one at low temperatures, to a non- 

 ductile, intercrystalline, and very brittle one at high 

 temperatures. A remarkable difference, however, is 

 that Rosenhain and Ewen found that the intercrystal- 

 line fracture occurred within a few degrees Qf the 

 melting point, whereas the present workers have 

 found that, in the case of copper, it is evident as low 

 as 720° C, or about 350° C. below the melting point. 



From time immemorial, manufacturers of zinc- 

 copper alloys have known that, at temperatures some- 

 what below a red heat, 60/40 brass becomes very 

 brittle, recovering its normal strength as it cools. 

 This fact was referred to by Bengough and Hudson 

 in a paper read to the Institute of Metals in Septem- 

 ber, 19 10. At the next meeting Carpenter and 

 Edwards showed that there was an arrest point occur- 

 ring at about 470° C. in the heating and cooling 

 curves of this alloy. They pointed out that this could 

 be explained by assuming either (i) that there was a 

 polymorphic modification of the /S constituent at this 

 temperature, or (2) that the ^ splits up into a+y. On 

 microscopic and other grounds they accepted the latter 

 view. In the discussion which followed the reading 

 of the paper, Mr. Hudson, amongst others, confessed 

 himself unable to accept Prof. Carpenter's interpreta- 

 tion. Since then the fray has raged more or less con- 

 tinuously between the supporters of the two theories, 

 and at this meeting, a paper has been read by Mr. 

 Hudson, which, in the opinion of the writer, definitely 

 settles the question in favour of the polymorphic 

 theory. Briefly, the j8 constituent has been syn- 

 thetised from a and 7 at temperatures below 470° C, 

 i.e. at a temperature at which the "decomposition 

 theory " supposes that it does not exist in equilibrium. 

 This result was obtained by annealing a piece of 

 70/30 brass in contact with a piece of zinc at a tem- 

 perature ranging between 420° C. and 430° C. ; after 

 annealing for several days, a section was cut at right 

 angles to the junction of the two metals, and it was 

 found that /S was present. 



The third part of Arnold Phillip's "Contribution 

 to the History of Corrosion " consists in a refutation 

 of the statement (made by Bengough and Jones in 

 their " Report to the Corrosion Committee ") that 

 coke in condenser tubes does not promote corrosion. 

 He brings forward eAndence to prove that the reverse 

 is the case. 



Thorneycroft and Turner continue the work com- 

 menced some years ago by Prof. Turner on the vola- 

 tility of metals in vacuo. The present paper describes 

 the results of experiments on the zinc-copper series, 

 and the authors show that those alloys containing 

 more than 40 per cent, of copper can be quantitatively 

 separated into their constituent metals by distillation 

 in vacuo, while in the case of those which contain 

 less than 40 per cent., part of the copper comes over 

 with the zinc. 



Amongst other papers read at the meeting is an 

 interesting one by Captain Belaiew, which has been 

 reprinted already in Nature (p. 107), a description 

 of the Schoop process of spraying metals by R. K. 

 Morcom, and a paper by S. W. Smith on the surface 

 tension of molten metals. J. L. H. 



