February 26, 1920] 



N A I'll RE 



705 



The same message reports that these observers find 

 remarkable changes in the spectrum of Mira Ceti, the 

 bright helium and hydrogen lines being strengthened 

 and widened towards the red. 



Tides in Pipes. — In 1914 Messrs. A. A. Michelson 

 and H. G. Gale made a preliminary investigation of 

 the tidal changes in water-level in two pipes, each 

 502 ft. long, placed respectively along a meridian and 

 a parallel, in the grounds of the Yerkes Observatory. 

 They have now made a more refined series of observa- 

 tions (described in the Astrophysical Journal for 

 December). The small changes of water-level are 

 registered by photographing interference fringes pro- 

 duced by placing a mirror about ^ mm. below the 

 surface of the water, and passing a beam of light 

 from an electric lamp vertically down through the 

 water-film, then reflecting it on emergence into 

 a camera in which a sensitive film is moved bv 

 clockwork at the rate of 2 cm. /hour. -Some of the 

 photographed curves are reproduced, and show a 

 beautiful accord with the theoretical curves, which 

 were carefully calculated by Prof. F. R. Moulton. The 

 transition from spring to neap tides, and even the 

 difference in height of alternate semi-diurnal tides, 

 are obvious at a glance. The result shows that the 

 pipe tides are o-6<)o of what they would be on a rigid 

 earth, so that the bodily tides in the earth's crust are 

 0-310 of what they would be if the earth were fluid. 

 The earth tides appear to lag behind the impressed 

 forces by 4°. This method avoids manv of the com- 

 plications that are present in the observation of ocean 

 tides ; it also appears to be capable of greater relative 

 precision, in spite of the smallness of the quantities 

 involved. 



There appears to be a slip in the value of the 

 rotational velocity <d (p. 350) ; it is printed as 

 2r sidl. day/solar day, but surelv it should be 

 ■277 solar day/sidl. day, the mean solar day being the 

 unit of time emploved. 



LUMINOSITY IN CENTIPEDES.^ 



A S Chilopoda have been traced back to the Car- 

 -^"^ boniferous age by the paleontologists, these , 

 centipedes may be presumed to have understood their 

 own interests pretty well in the struggle for exist- 

 ence. GeophUus electricus (Linn.) had already won 

 the attention of .Mdrovandi in the sixteenth century, 

 and the specific name adopted , for it by I^innaeus was 

 obviously based on its observed luminosity. The notes 

 now under review state that among the centipedes 

 only one great group, the Geophilimor[)ha, is known 

 to exhibit the phenomenon. 



With so long a history for the group in the modern 

 jseriod, it seems strange that biologists should still 

 need to ask in regard to some of its species, which 

 are by no means uncommon : Whv are thev luminous? 

 Even those keen observers, Mr. and .Mrs. Brade-Birks, 

 after minute examination, with the aid of friends, 

 and critical comparison of recent authorities, leave the 

 subject inconclusively concluded. Microscopists will 

 read with pleasure details of the contrivances bv 

 which they persuaded their many-legged, wriggling 

 subjects, under just the friendliest squeeze, to sit for 

 their portraits. As definite result of their careful 

 studv of GeophUus carpnphagus, thev "conclude that 

 in the excretion which accompanies luminosity there 

 are generally present : (i) the contents of the white 

 glands, for fwhich theyl propose the name of proto- 

 luciferin, (ii) mucin, (iii) acid." The expression 

 " white glands " seems to be used rather vaguelv, as 



1 Bartford Naturalists' Field Club Occasional Papers. Notes on Myria- 

 poda. XX. "Luminous C^^ilopoda, with Special Reference to Geof<kilus 

 carpophagvs, I.each. " By Hilda K. Brade-Birlcs and the Rev. S. Grabam- 

 Birks. 



applying to certjiin white, rounded masses on the 

 ventral parts of the specimen, these masses being 

 •"groups of pyriform, and probably unicellular, glands 

 intimately associated with the production of light." 

 But it is not made clear whether whiteness is a pro- 

 perty of individual glands or only an effect of their 

 grouping into opaque masses. 



For an understanding of the debate on the value 

 of lighting up as displayed in this very limited section 

 of the animal world. Dr. Shipley's brief notice may 

 usefully be quoted. He says : — " Some members of the 

 family Geophilidse are phosphorescent, and secrete 

 from certain glands on the ventral surface a luminous 

 slime; since this is produced by both male and female, 

 and neither of them has eyes, the secretion is regarded 

 as a means of frightening or warding off enemies. 

 The male Geophilus spins a web, and drops a 

 spermatophore in the middle of it, and the female 

 comes and fertilises herself" ("Zoologv of the Inverte- 

 brata," p. 315). The present collaborators suggest 

 that, without specialised organs of sight, the Geo- 

 philids "may be able to appreciate light by a general 

 absorption of its waves through the surface of the 

 body." Though this inchoate power of vision might 

 be otherwise of service, it could scarcely help in 

 bringing the two sexes together, and the' riddle is 

 complicated by the fact that allied species without 

 luminosity seem to arrange their affairs very well in 

 its absence. 



In general, exi>erience has shown that animals, 

 other than beasts of prey, are not frightened, but 

 attracted, from a dark environment by illumination, so 

 that among the alternative services of proioluciferin 

 suggested by the authors any scaring propertv may 

 be set aside as very improbable. 



The .systematist is now warned by our authors that 

 Stigmatogaster subterraneus should be attributed to 

 -Shaw. So lately as last December, in Nevin Foster's 

 list of fiftv-three Irish Myriapods, thev sanctioned the 

 long-standing error of assigning the species to Leach. 

 They acknowledge them.selves baffled' by the specific 

 name of Geophilus convolvenx, on which Fabre 

 founded his researches. This is said to be not a 

 phosphorescent species. Otherwise one might have 

 supposed the name evolved from the strange account 

 which Lucas cites out of the C.R. Acad. inMcale 

 des sciences de Metz in 1830. This records the fright- 

 ful tortures in the head of a voung Frenchwoman, 

 which after a year were suddenlv terminated "par 

 I'expulsion d'un insecte qui, ]et^ sur le planch'er, 

 s'agitoit avec rapiditf^ et se rouloit en spirale." It, 

 however, was determined to be a soecimen of Geo- 

 philus carpophagiis. Leach. Gistel in t8;o. writing 

 of the Feuorwurm Geophilus electricus. alludes to the 

 storv, but does not, in fact, discredit it bv rpmarkinf» 

 that such a soecies could not penetrate the frontal 

 cavities of a human head unless the owner of the 

 head were asleep. T. R. R. S. 



NO. 2626, VOL. 104] 



THE POSITION OF THE METEOR- 

 OLOGICAL OFFICE. 



AT the monthly meeting of the Royal Meteoro- 

 ■^*- logical Society, held on Februar'v 18, Capt. 

 C. J. P. Cave brought forward a paper on "The 

 Status of a Mteteorological Office and its Relation 

 to the State and to the Public." It was pointed out 

 that a Meteorological Office is a practical necessity, 

 and, since to be at all efficient it must be subsidised 

 from public funds, it has to be under some Govern- 

 ment Department. The work of a Meteorological 

 Office is, however, very wide, and concerns, not one, 

 but almost every Government Department; and if it 

 is to be under one without adequate safeguards, there 



