17" 



NATURE 



[October 31, 1918 



show thai the Eransfoi mai ion occi g after 



this range is constant is independent ot thi 

 in which the cold work is applied. Beyond E, how- 

 ever, the new curve does not coincidi ivith ED, bnt 

 rises more steeply, the tensile strength corresponding 

 with the 0-040 in. diameter wire, I . ing nearlj ;; tons 

 per sq. in. It would appeal , then, that thi change taking 

 place along ED is different in type from that occu 

 along AL. It is stilted thai wins of such a diameter 

 that they fall within the rangi \K an stable at Mm 

 ordinary temperatures Vi in; rate, the) do not 

 change in a year's time. ' )r i the other hand, (vires 



corresponding with the p ts on the branch ED are 



unstable at atmospherii temperatures, their tensile 

 strength being gradually diminished. Finally, Mr. 

 Alkins records that, if fully annealed win- of anv 

 diameter is taken and drawn down, a stage is always 

 reached, when its area has been reduced about ;o i" i 

 cent., where, over a limited range, furlhei drawing 

 ponding alteration in the properties. 

 He finds tli a 1 the physical properties corresponding with 

 this constant range are always the same — e.g. den- 

 sity = 8 889, tensile strength = 23-2 tons per sq. in., and 

 so on. He concludes, therefore, that the point E 

 corresponds with a definite nh\si,al State of the metal. 

 The facts thus brought Forward by Mr. Alkins are 

 of definite practical importance and distinct scientific 

 int. rest. Considering tile importance of the point E, 

 it would have strengthened his case if he could have 

 shown rather more observations in its immediate 

 neighbourhood. This, of course, would have involved 

 the preparation of a new set of rolls, bv which verv 

 slight differences in area could be effected. Such work 

 cannot, of course, be undertaken under war condi- 

 tions. Further, he would have been well advised to 

 determine the percentage of copper-cuprous oxide 

 eutectic in his wire, which he did not do. This omis- 

 sion can, of course, be remedied, and until it is, and 

 the influence of oxide specifically determined, no one 

 can sav how far his results are due to copper itself. 

 If and when these omissions can be remedied, Mr. 

 Alkins will improve a paper which already does him 

 very great credit. H. C. H. Carpenter. 



THE RAT PEST. 



T3 EFERRING to Prof. P. Chavigny's report on rats 

 ■^ in the trenches (Nature, September 19, p. 53), 

 Mr. C. B. Moffat, Enniscorthy, points out that the 

 descendants of a pair of rats must in three years far 

 exceed the twenty millions stated. At the end of the 

 first year there should be 50 offspring, 500 grand off- 

 spring, 1000 great-grand offspring, 1250 great-great- 

 grand offspring 2800 in all. Half of this number, sup- 

 ui all is equal males, multiplied by 2800, gives 

 1 iIh end of the second year. At the end 

 of the third year the number, should be far more 

 than li\i thousand millions. It has to be borne in 

 mind, ho lat f' male rats probably reach their 



limit ot 1 1 long bi fore three years. The most 



secure data known to us are those of Helen Dean 

 Ring (.bin/. Record, vol. xi., rqici, pp. 269 87) on 

 70 females 1 cross between the wild 



\'oiw.i\ 1. 11 1 -mated white rat. The 



11 mi - was 67 (Prof. Chayigny 



speaks of to); thi . . number of litters t.n .1 



female was 7-; there is a sh:trp decline in fertility 

 after the femati 1- . old and the menopause 



appears al eighteen month I sex ratio for 3955 

 individuals was ro6-1 mail ■ We do 



not know how Prof. < ha 1 n ;,, ,1 the figure 



twenty millions, hut. as Mr. Mol lises, there 



-re various biological ronsideraii' h maki Ihe 



imputation not so simple .is it eem fh si. 



NO. 2557, VOL. I02 



\\ ithout doubt the iq< h and info, 



tive summary of the menao which lares us from thi 

 hordes oi rats and mice in our mids been 



issui 'I lis tin 1 rustees of the British Musi urn 1 Natl 

 History 1, forming No. 8 of trie Eeonomii Series issi 

 l>\ 1I1. 11 institution. The author, Mr. M. A. 1 I I ■■ . 

 one el ill. greati -1 living authorities on ibis -nl.,. 1 ., 

 has marshalled his faets with extraordinarj skill; so 

 much so that he has contrived, within the space of 

 some sfxt) pages, to pass in review, not onh the life- 

 history of these p sis in a state of nature, 

 relation to public health, and their amazing destrue- 



li\en, ss in the matter of our food supplies, bill al-.. 

 the various preventive measures which afford us mi 

 of relief. On this head he has much to say in con- 

 demnation of the destruction of so-called "vermin," 

 which, until now, has been so pei sistenfly .and stup 

 followed. Finally, he add- .1 most v.duai.l. .1,, 

 on the classification of the Murnke, and a tabli sh 

 ing the assumed rate of increase in the annual. 1.1 

 population, which, even white postulating a mortality 

 which is purposely exaggerated, shows clearrj enough 

 that none but the most determined efforts can hope 

 to lessen the seriousness of the situation, which has 

 1 linn about owing to the withdrawal of all labour 

 hitherto devoted to the destruction of rats, either bv 

 the needs of the Army or by the allurement of the high 

 wages paid for other kinds of work more or less 

 directly arising out of the war. A number of well- 

 chosen and beautifully executed illustrations, showing 

 the dental and cranial characters by which our native 

 spe. i,s of Muridas may be distinguished, add still 

 further to the value of these pages. But the figures of 

 the black and common rat and of the house-mouse, 

 to say the least, leave much to be desired. This 

 pamphlet should be carefully studied, not only hv the 

 agriculturist, the merchant, and those responsible for 

 the preparation of food in restaurants, but also by the 

 housekeeper; for it is only by the concerted efforts 

 of us all that we can hope for success in this cam- 

 paign, which is noiv to he commenced against a 

 condition of affairs which is fraught with real peril. 



THE RALEIGH TERCENTENARY. • 

 "THE tercentenary of Sir Walter Raleigh's death was 

 ■^ celebrated on Sunday, October 27, by a special 

 service at St. Margaret's Church, Westminster. The 

 service was arranged by the Tercentenary Com- 

 mittee, of which the Ring is patron, Mr. 

 Balfour one of the honorary presidents, and Prof. 

 Gollancz hon. secretary. Two wreaths in memory 

 of Sir Walter Raleigh were laid before the service at 



the I. if the Communion-table, where the body is 



said to have been buried. One was from the Tercen- 

 tenary Committee; the other, of laurels, was from the 

 Royal Geographical Society, and was inscribed: "To 

 the memoi 5 of Sir Walter Raleigh on the tercei 

 of his death." It was borne by Sir Thomas Holdich, 

 K.C.M.G., and Mr. Arthur K. Minks, secretary of 

 the society. The address was delivered hv the rector 

 of St Margaret's, Canon t arnegie. Memorial ser- 

 vices were also held at the Temple Church and at 

 Woolwich Parish Church. Ihe work of Raleigh in 

 exploration and colonisation was also commemorated 

 ..n I in s,la\ by meetings at the Mansion Housi and 

 els, w in re. \t the Mansion House meeting Sir (diaries 

 Wakefield (hon. treason 1 of the Terccntenaiw Com- 

 mittee) offered for the acceptance ot the Lieutenant 

 of the Tower a copy of Raleigh's "History of the 

 World," which he hoped would find a place in 

 where the history was written. lie offered to the 

 British Academy as th." mul. 11- of a Raleigh Fund for 

 llisioi . ihe sum of =;oo/. a year foi at least 



