September 19, 1918 



XML- RE 



lui Spbctroscoph 1>i\m;\ Boss 40. Following 



1I1, j ij this star .a 



Mouni Wilson in 1914, Messrs. W. s Vdams and 



1, Sti nberg have mad< extensive observations, ami 



spei ial inti n si have t *« • - 1 1 revealed 



rophys. Jown., vol. \lvii., p. 329). The star 



belongs t>> the class <>t binaries in which 



th( calcium lines give values of the radial velocit) 



rig uid.lv from those indicated b) other lines. 



'I'h. period i- 3-5225 days, and trie velocity shown by 



the hydrogen and helium lines ha- the remarkably 



m. pei sei ond. I hi calcium 



have been found t<> shew a variation having the 



same period, but with tin- comparatively small range 



of -'.. km. A velocit) of 4.-; km. for the system is 



.,! hydrogen and helium, and 



of —23-5 km. In the calcium lines. Thesi results 



seem to favour the view thai the vapour producing 



the .allium lines is not in the form ol a detached 



-ut is involved in the binarj system 



itself. Mf din. lint; velocities foi the system ded 



from the two sets of fines an probably not tobewholly 

 inter| basis of velocity. The visual magni- 



tude ..I tli.' -tar is tvo. and ih.' spectral type B.sp. 



THE IN] ISION <>/• TRENi HES Bl R ITS. 



PROF. IV < II WIGNY ha- contributed to the Revue 

 Generate des Sciences for July 15 and jo two very 

 ig and useful articles on the invasion ol 

 trenches - ench warfare began 



riches -were Invaded b) immense numbers 

 ol rats, which caused great damage and almost in- 

 tolerable annoyance at night. Various measures, 9uch 

 as tin- u-. ..I poisons, infective virus, traps, terriers, 

 etc, were taken to destroy the rats, hut with very 



CCeSS; and it is shown that this was due to 



a lack of knowledge of the natural history and habits 

 of the animals concerned. 



The rat which invades trenches i- nearlj always 



tin- ordinal) brown or Norwaj 1.1 1 (Mus decumanus), 



but in the .as. of dry trenches the black rat {.\1. 



rattus) may be present. These rats sleep in places ol 



• hole- during the da) ; ii is at night that 



iuse all the trouble. The intelligence which 



splaj in overcoming obstacles and avoiding 



iry ; and it is evident 



that the} pos 1 5s -iin. mean- ..i communicating theii 



knowledge to one another, -inc. an) particular means 



of killing them soon become- ,,f little use. Prof. 



Chavignj lays special stress on the fact that they 



live on exactlj the same food a- man, and cooked 



1 )l raw food the) can make -1 n 1 . 1 



mce, the) simpl) starve if given 



raw barley. The) will gnaw ami destro) almost any- 



,11 ih,;, teeth .an penetrate, but what they 



actually live upon i- simply the ordinary human food 



which they are able to reach, and particularl) the 



remnants front meals. A rat consumes about 30 to 



- 1 1 daily, ami starvation kill- it in 



irty-eight hours. It neither lays up stores of 

 food nor hibernates in winter. 



\- ordinal, brown and black rats will not breed in 



captivity, most of out- knowledgi as to theii rate ol 



ion i- derived from observations on the albino 



variety, which breeds readily in captivity. The period 



ion i- twenty-one days, ami the minimum 



tim. between two litter- from the same female is 



sixty-two .lavs, she ma) hav« as many as five litters 



. A litter consists of about ten. A female 



at the age of two and a half to three months is 



capable of producing a litter. The young ar. ven 



efficiently tended, so that scarcely anj die. \ simpli 



calculation gives the surprising result that a sin^l. 



255 I . VOL. IOJ" 



I pair ol rats is capabli 1 1 producing tweim million 

 descendants within thr< 1 



Reproduction ceases during ither, and 



laniin themselves at all in cold climates. 



In temperate climates rep u 1- at a standstill 



during the winter. The most important factor limit- 

 ing reproduction i-, howei il of nutriment. 

 A female receiving onl) suffii i , her in 

 -..oil condition does not reproduci a tereas with 

 superabundance of food reprodui ds at its 

 maximum rate. 



In his second paper Prof. Cha cribes and 



isses the various methods used fot d. rats. 



mil -how- that the disappointing results 1 



11 to neglect oi the fael that multiplication il rats 

 i- simply the result of scattering human food within 

 1 inn 1 . .1. Ii. 111. essential step in ccmti oiling thi 

 invasions i- 10 prevent the scattering about of remnants 

 of food. For this purpose it is recommended th 

 where possible, all waste food should be colli cted and 

 used for pigs. Where this is not possible the v 

 food should be thrown into pits and covered with 

 earth before nightfall. Prof. Chavigny proposes also 

 that placards should be posted up saying that "he who 

 sows fragments of food will reap a harvest of ra - 



THE PROPERTIES OF COPPER. 



THE U.S. Bureau of Standards has recently issued 

 a circular (No. 73) entitled "Copper." It appears 

 that the Bureau is constantly in receipt of requests for 

 detailed or general information concerning the proper- 

 ties, statistics, etc., of metals and alloys. Such in- 

 formation is rarely to be found in systematic form. 

 Generally the different sources of such information are 

 difficult of access, and their accuracy is not always 

 certain. Much information of this kind that is quoted 

 is valueless, either for the reason that the data upon 

 which it is based are incorrect or because they have not 

 been properly interpreted in quoting. Accordingly, the 

 Bureau is planning to issue from time to time circulars 

 on individual metals or alloys with the idea of grouping 

 in them all the most trustworthy information that is 

 available, either from its own tests and investigations 

 or from published records contained in the literature. 



These circulars are intended to deal primarily with 

 the phvsical and mechanical properties of the metal 

 or allov; all other factors, except a few statistics of 

 production, such as methods of manufacture, impuri- 

 ties, etc., are discussed only in relation to these proper- 

 ties. Copper has been chosen as the firs! metal for 

 this treatment, partly because much of the accurate 

 information regarding it has been obtained at the 

 Bureau, and partlv because our knowledge of its pro- 

 perties is more complete than that of an) other metal. 

 Moreover, the commercial forms of copper are charac- 

 ti rised by a high degree of purity, e.g. the electrolytic 

 wire bar manufactured in the United States of America 

 contains on an av. 96 per cent, of this metal, 



and the Lake wire 89 per cent. The highes 



quality brands of English (furnace-refined) copper con- 

 tain about 9975 P< I 



Circular No. 73 contains the best established 

 values of various phvsical and mechanical char- 

 acteristics of pure and commercial grades 

 copper, principally at the ordinary temperature. Varia- 

 tions of these properties wdth changes of tempo 

 are al ussed. There is a useful techn logical 



dealing with casting, deoxidation, - rking,. 

 welding, hardening, electro-deposition, and heat- 

 treatment, followed bv another discussing the 

 of impurities on the phvsical proper! metal, 



and concluding with a brief aci oui - asi - 



A complete bibliography and typii il specifications are 



