October 2, 1919] 



NATURE 



93 



mica is to be ascribed more to special uranium- 

 richness of the nucleus rather than to the antiquity 

 of the rock. The rock is a biotite granite with a 

 white and a yellow felspar. It is said to be from 

 Sinai. One side of the specimen has been exposed 

 to the weather, and the appearance of this side 

 suggests desert conditions. 



J. JOLY. 



J. H. J. Poole. 

 Trinity College, Dublin. 



The Spectra of Isotopes. 



So.ME years ago I made an investigation of the 

 spectra of ordinary lead and lead from pitchblende 

 residues, but I was not able to detect any difference 

 in the spectra. More recently Aronberg {Astrophys. 

 Journal, February, 1918) has found a difference in 

 the wave-lengths of the principal line in the sf>ectra 

 of ordinary lead and lead from Australian carnotite 

 amounting to 00043 ^- ^ have made a fuller investi- 

 gation of the problem by a method of experiment 

 greatly superior to that which I had previously 

 adopted, and the results show that there is a small 

 but real difference in the spectra, which agrees closely 

 with the value found by Aronberg. A difference has 

 also been found between the wave-length of the prin- 

 cipal line in ordinary lead and lead from Ceylon 

 thorite. 



These results at once suggest that the spectroscope 

 will furnish a simple and comparatively rapid method 

 of distinguishing isotopes, and some measurements 

 have been made of the wave-lengths of the principal 

 line in ordinary thallium and in thallium from pitch- 

 blende residues. It has long been susp>ected that, in 

 addition to lead, some of the metals found in pitch- 

 blende may be of radioactive origin, and the results of 

 the wave-length measurements, though for certain 

 reasons they cannot be given the same weight as those 

 relating to lead, suggest that the thallium in pitch- 

 blende is an isotope of ordinary thallium and more 

 probably of greater atomic weight. It is hoped to pub- 

 lish shortly an account of the investigation. 



Thomas R. Merton. 



Balliol College, Oxford, September 15. 



A British Imperial Antarctic Expedition. 



May I, through the columns of Nature, direct 

 attention to the British expedition which I am at 

 present organising and propose to lead to the Ant- 

 arctic in June next year? Theobjects of the expedi- 

 tion are briefly as follows : — 



(i) To ascertain the position and extent of the 

 mineral and other deposits of economic value already 

 known to exist in Antarctica {vide scientific reports 

 of Bruce, Mawson, Scott, and Shackleton), and obtain 

 data for the practical development as a further source 

 of Imperial wealth. 



(2) To obtain further evidence of the localities of 

 whales of economic value, and to create British indus- 

 tries in this trade. 



(3) To investigate the meteorological and magnetic 

 conditions in the Ross Sea area and at Cape Ann 

 (Enderby Land) in connection with their influence 

 under similar conditions in Australasia and South 

 Africa respectively. That such results are of great 

 sconomic value has been proved by the station estab- 

 ished by the Argentine Government for similar pur- 

 joses in the South Orkneys. 



(4) To circumnavigate the Antarctic continent. 



(5) Generally to extend our knowledge of Antarc- 



NO. 2605, VOL. 104] 



tica, especially with the view of obtaining further 

 scientific data of economic importance. 



The expedition proposes to leave England in June, 

 1920, and to be away for a period of live years. 

 During this period important scientific research will 

 be vmdertaken on the lines briefly given above. 

 Applications are invited from fully qualified men in 

 the following branches of scientific knowledge : — 

 Geology, meteorology, biology, surgery and physio- 

 logy, photography, cartography, and hydrography. 



The expedition has been well and strongly sup- 

 ported, and I shall be glad if all who are interested 

 will communicate with me at the address given 

 below John L. Cope. 



66 Victoria Street, London, S.W.i, 

 .September 20. 



Luminous Worms. 



When I wrote the letter which appeared in Nature 

 of September 1 1 (p. 23), I made no reference to my 

 impression that a friend had seen luminous earth- 

 worms in Great Britain because I was not aware that 

 he was still in England, and was consequently unable 

 to give accurate details. I found afterwards that 

 this friend. Dr. Edgar Newbery, recently appointed 

 professor of physical chemistry in the University of 

 Cape Town, had not yet left this country, and I was 

 able to write to him for confirmation of the impression 

 in my mind, and I have now received a reply. Writing 

 from Byton Rectory, Presteign, Radnor, Prof. Newbery 

 says : — 



" I have seen luminous eartlfworms on more than 

 one occasion on the grass of our lawn here. (We are 

 reallv in Herefordshire, though our post town is in 

 Radnor). The soil from which they emerged is a 

 mixture of clay and gravel, but is very fertile. The 

 luminosity was very weak, and gathered in spots or 

 blotches over the body. Small luminous patches were 

 left behind on the grass in the track of the worm, but 

 these faded in a very short time (30 seconds or so). 

 I have seen them both in warm weather and when a 

 slight frost was on the ground, but a very dark night 

 is necessary to render them at all conspicuous, as the 

 luminosity is so weak." 



That Prof. Newbery is not confusing luminous earth- 

 worms with luminous centipedes is concluded from the 

 next paragraph in his letter : — 



"On Tuesday, September 2, I saw a remarkably 

 brilliant luminous centipede in a barley field 100 yards 

 from here. The light was so vivid that it caught 

 my attention at a distance of 12 yards, and the 

 luminous trail left behind it was quite 12 in. 

 long. ..." 



Suggesting the cause of luminosity. Prof. Newbery 

 says : — 



" I am inclined to believe that the luminosity of 

 these centipedes and worms is due to slow oxidation 

 of some excretion from the body which may well be 

 affected in quantity and quality by the food available." 



So far as centipedes are concerned, I think Dr. 

 Brade-Birks and I shall be able to show, in a forth- 

 coming paper on luminous Chilopoda, that atmospheric 

 o.xygen is not necessary for the production of light in 

 the centipedes we have studied, but Prof. Newbery's 

 suggestion about food supply may explain why some 

 individuals of a species are luminous while others 

 are not. 



In VerhoefT's "Chilopoda" (Bronn's " Klassen und 

 Ordnungen des Thier-Reichs ") there is no reference in 

 the bibliography to Dr. T. L. Phipson's "Phosphores- 

 cence, or the Emission of Light by Minerals, Plants, 

 and .'\nimals " (London : Lovell Reeve, 1862); I there- 



