SSo 



NA TURE 



[December 30, 1922 



right angles, others were fitted with ordinary rivets 

 and bolts, while others were bolted one to the other. 

 When all the bars had been carefully weighed they 

 a ked in tin-lined cases and despatched to their 

 respecl \\ e destinations. The committee arranged that, 

 at each place, one set of bars should be completely 

 immersed in sea water; one immersed at half tide 

 level, thereby becoming alternately we1 and dry; 

 and one set should be exposed to the sea air only. 



When this comprehensive piece of research work 

 is completed, the results should be of the greatest 

 value not only to engineers but to all concerned in 

 the use of ferrous metals. 



Sir Robert Hadfield also gives an interesting account 

 of the employment by the Admiralty of stainless steel 

 during the war. Considerable difficulty had been 

 experienced in consequence of the rapid corrosion of 

 the diaphragms used in connexion with submarine 

 hydrophones, which were put out of service in a com- 

 paratively short time. Messrs. Hadfield submitted 

 experimental diaphragms of steel containing about 

 36 per cent, of nickel, ami others of steel with a 12 to 

 14 per cent, chromium content. The latter alloy, 

 the so-called "stainless steel,'' quickly proved its 

 superiority, anil was finally employed for the hydro- 

 phones. Although the nickel steel was very resistant 

 to corrosion, its acoustic properties were not so good. 

 These depend not only on the hardness of the metal 

 but also upon its elastic limit, in both of which points 

 the chromium steel was the superior. The diaphragms 

 were placed in the hull of the submarine several feet 

 below the water line, and it was noticed that although 

 the surrounding plates of ordinary steel were soon 

 covered with barnacles the chromium steel was entirely 

 free. One of the diaphragms, after having been 

 immersed 111 sea water under service conditions for 



six months was found to have undergone practically 

 no alteration. A small film of a dark-brown deposit 

 was noticed patchwise here and there on the surface, 

 but this was easily rubbed away with the finger, 

 revealing the bright metal beneath. 



(in- diaphragm did manifest local corrosion, and a 

 photomicrographic examination revealed a coarse grain 

 due, in all probability, to over-heating. A portion 

 was suitably heat-treated and restored to a normal 

 condition, after which it showed the usual full resist- 

 ance to corrosion. 



As this chromium steel is one of the metals employed 

 by the Corrosion Committee in their programme of 

 tests, it will be particularly interesting, in view oi the 

 foregoing results, to see how this metal behaves. 



In conclusion Sir Robert Hadfield very rightly directs 

 attention to the economic importance of the problems of 

 corrosion. Accurate statistics on the subject are, for 

 obvious reasons, unobtainable, but Sir Robert estimates 

 that the annual cost of wastage due to rusting is probably 

 well over 700 million pounds sterling, this sum includ- 

 ing an estimate for the cost of galvanising the metal, 

 and allowance being made for painting, sheathing, 

 etc., all of which processes would usually be unnecessary 

 it tin- metal were not so prone to oxidise. 



One feature of this estimate deserves special attention. 

 The amount of the annual production of iron and steel 

 by no means represents an equal increase in the world's 

 stock of these materials. The quantity swallowed 

 up merely in replacing wastage is enormous. We 

 unite with the author in the hope that his memoir 

 " will arouse still more attention than the subject has 

 received in the past, and will create greater interest 

 in the production of alloy steels, which have the 

 capacity of resisting corrosion, if not entirely, at any 

 rate to a much greater excent." J. N. F. 



The American Museum of Natural History. 



THANKS to the ideals of its president, the en- 

 thusiasm of its staff, and the abundant illustra- 

 tions, the reports of the American Museum of Natural 

 History are always interesting reading, and that for 

 1921 forms no exception. Indeed the president. Prof. 

 H. F. Osborn, lays particular stress on this report, and 

 he has reissued certain pages of it in a neatly bound 

 booklet under the title of " The American Museum 

 Ideal." That ideal he expresses in the words of 

 Francis Bacon : " a model of universal nature made 

 private. ... A goodly huge cabinet, wherein what- 

 soever the hand of man by exquisite art or engine hath 

 made rare in stuff, form, or motion ; whatsoever 

 singularity, chance, and the shuffle of things hath 

 produced ; whatsoever nature hath wrought in things 

 that want life and may be kept, shall be sorted and 

 included." 



In short, the American Museum is become a world 

 museum, and to that end it is sending out its explorers 

 all over the world to gather and compare both for the 

 benefit of Americans and for the benefit oi everj 

 country which they may visit. Acknowledgment is 

 made of the cordial co-operation which the American 

 Museum receives from the Governments and scientific 

 institutions of all those countries, while at home, 



NO. 2774, VOL.* I IO] 



thanks to the large development of the educational 

 side of its work, the museum continues to enjoy strong 

 support from the city government. By the latter at 

 the end of last year the sum of 1,500,000 dollars was 

 unanimously voted for the erection of two new sections 

 of the building as originally planned in 1875. There 

 is also under consideration, as previously noticed in 

 Nature, a special school service building to be devoted 

 exclusively to school education in all its grades. 



Prof. Osborn's ideal, however, goes far beyond this. 

 He says, " It is evident that astronomy will be the 

 central feature of our plans, because all the processes 

 11I earth's history and all the processes of life centre 

 around original astronomic causes." Plans for an 

 astronomical hall have already been drawn up and pub- 

 lished, and have been confirmed by the trustees. All 

 that is wanted is the money. It is estimated that the 

 buildings when finished will cost not less than 9,000,000 

 dollars, and Prof. Osborn calls for a new general en- 

 dowment of 2,000,000 dollars. This Litter, lie says, will 

 not only restore the museum to its full-time efficiency, 

 but will enable it to prepare to keep its promise to the 

 iitv government; and when its Asiatic and Oceanic 

 sections are completed the museum will be able to fill 

 them with the specimens now in store, including many 



