342 



NA rURE 



[August i i, 1904 



.and, what is most remarkable, Xhc rodio-nclivily -a'cis re- 

 moved fcv washing with -water. The solution contains an 

 emanation, for on bubbling air through it, and cooling the 

 gas with liquid air, the issuing gaseous air is only feebly 

 active ; the main part of the activity was retained in the 

 cooled bulb. This substance can be carried into an electro- 

 scope by a current of air, and when the current passes, the 

 electroscope is discharged ; but the period of decay of the 

 emanation is very short, and in that respect resembles the 

 emanation from actinium. 



The research is not sufficiently advanced to permit of a 

 complete account of the other products, but it may be 

 mentioned that from the solution which has lost all eman- 

 ating power further active products are obtainable, some of 

 which are precipitable along with mercurous chloride, some 

 along with mercuric sulphide, some with ferric oxide, and 

 some with barium sulphate. The behaviour is different, 

 according as potash- or soda-glass is used. That this is not 

 a case of a body being thrown down by any precipitant has 

 been abundantly proved ; for example, precipitation along 

 with mercurous chloride or sulphide failed to remove tlie 

 activity from one sample, while the precipitation of ferric 

 hydro.xide in the solution completely threw down the radio- 

 active material. There appear to be several radio-active 

 bodies present which can be separated by the ordinary 

 processes of qualitative analysis. 



These substances, it must be remembered, are the products 

 of y3 and y rays in conjunction with the material on which 

 they impinge. A silver crucible, too, becomes radio-active 

 on the exposed surface only when placed in the path of /3 rays. 

 It is important to note that these changes are not due to 

 the material having been in contact with radium or any of 

 its products; they are solely due to the ,8 and possibly to'the 

 y rays. The order of the activity is the same as that of 

 I milligram of old uranium oxide, U,0,. 



WlLLUM Rams.w. 

 \V. Ternent Cooke. 



University College, I^ondon, July 30. 



Atomic Structure in the Light of Secondary Spectra. 

 In making some determinations of the capacity necessary 

 just to produce secondary spectra, I have found that this 

 critical capacity increases very rapidly with decreasing 

 w-ave-length. The primary spectrum does not go over 

 suddenly as the critical capacity is reached, but the red and 

 yellow portions go over first, then finally, at a much greater 

 capacity, the violet. Critical capacity as a function of 



wave-length is well represented by the exponential f *" ^, 

 approaching a constant value in the infra-red and the value 

 infinity in the ultra-violet, perhaps not farther out than 

 250^^1. 



Consider the radiation from a nitrogen atom. When 

 subjected to feeble electrical excitation its (primary) spec- 

 trum is banded, each band being composed of numerous lines 

 not showing the Zeeman effect. But when subjected to 

 excessive excitation, as it is when a large condenser is con- 

 nected in shunt with the conducting gas, its (secondary) 

 spectrum consists of numerous heavy lines, showing the 

 Zeeman effect, and expressible in Kayser-Runge series. 



Runge, having in mind the Zeeman effect, supposes that 

 primary spectra are due to positive ions w-hile negative 

 electrons give secondary spectra, but it is hardly conceivable 

 that feeble excitation should all go to the positive ions 

 while more intense excitation all goes to the negative. 



I would suggest that an atom composed of rotating rings 

 ■of electrons according to recent theories might easily 

 exhibit just such radiating properties as would give primary 

 and secondary spectra, together with the variation of 

 critical capacity with wave-length. Suppose that there are 

 as many rings as there are bands in the primary spectrum. 

 With moderate excitation these rings would vibrate radially 

 and tangentially as well as perpendicularly to their planes, 

 and these vibrations would give rise to the lines comprising 

 each band. Such lines would not show the Zeeman effect. 

 K.\cessive excitation would break up the rings and allow 

 the electrons to move independently. Radiation from such 

 free electrons would constitute the secondary spectrum, and 

 would show the full Zeeman effect. The larger rings would 

 be the first to break up; the smallest rings, perhaps, could 

 not be broken up at all, hence critical capacity would vary 

 NO. 1815, VOL. 70] 



with the wave-length and become infinite for moder.itely 

 short waves. Metallic atoms have ring .systems that are 

 so easily broken up that it is impossible to obtain any 

 primary spectrum from them at all. 



Washington, D.C. 1'. (... Nutting. 



The Flowering of the Bamboo. 



Can your botanical readers give me any information about 

 the flowering of the bamboo? Until recently I was not 

 aware that it presented any extraordinary features, but 

 about the middle of April the bamboo in this locality pro- 

 duced flowers, to the great astonishment of everyone long 

 resident here. The peasants, and many of the more 

 ignorant townspeople, regarded the event with much 

 superstitious terror. It is supposed by them to portend a 

 failure of the crops, and possibly even more serious disasters. 

 A small anti-tax rising, some distance away, appeared for 

 a few days to be a serious matter, and as it was in progress 

 during the time at which the bamboo flowers appeared, many 

 were inclined to exaggerate enormously the danger of the 

 situation. These superstitious terrors (closely resembling 

 the fears formerly aroused in Europe on the appearance of 

 a large comet) sufficiently show the rarity of the pheno- 

 menon. 



On making inquiry, I could only hear of one man (I did 

 not myself meet him) who had ever seen the bamboo in 

 flower before. 



I am told that a species of bamboo in southern California 

 flowers annually, the flower being at the top of the plant 

 only. In the species growing here the flowers were at all 

 heights, arranged at frequent intervals along almost every 

 branch of the plants. I obtained a photograph of a spray 

 in flower, but unfortunately it is so small that the distinc- 

 tion between leaves and inflorescences is very imperfect. 



.'\. Tingle. 



Imperial Provincial College, Chinanfu, Shantung, 

 China, .May. 



As regards the point raised by your correspondent, I may 

 say that the feeling of alarm aroused in the natives by the 

 flowering of the bamboo seems to be widely spread in the 

 East. I have myself heard of it when in India. 



The fact is that the bamboo only flowers once and then 

 dies, and as a rule the whole lot of plants, often covering 

 large areas, bloom together. 



The reason of this is that the individuals of a species are 

 commonly gregarious, and are all of the same age, having 

 taken simultaneous possession of ground rendered vacant, 

 perhaps, by a previous and similar depopulation. 



.\ somewhat analogous case is presented by some of the 

 Strobilanths of tropical Asia. These plants live for about 

 seven years, then all burst out into a glorious mass of 

 blue flower, and then die away, leaving, it may be, hundreds 

 of acres of ground destitute of the luxuriant vegetation it 

 previously supported. 



Dr. O. Stapf, in a most interesting article that appeared 

 in the Gardener's Chronicle this year (Nos. 907-910), gives 

 an account of the introduction into Europe of two bamboos 

 that have suffered a similar fate. 



In 1847 seeds of Ariindinaria Falconeri (and another 

 species) were received at Kew-, and were thence distributed 

 to various gardens, some finding their way to the Continent. 

 The plants flowered (and then died) in France in 1875, and 

 in the following year all the English plants, growing in 

 different localities, shared the same fate. 



J. B. Farmer. 



Claremont House, Wimbledon Common, August 2. 



The Organisation of Zoologists. 



May I be allowed to direct the attention of the readers of 

 Nature to the fact that a meeting of zoologists will be held 

 in the comparative anatomy lecture room at Cambridge on 

 Wednesday, August 17, at 4 p.m., to consider a scheme 

 for organisation suggested by the committee that was 

 appointed in London on January 4. The suggested scheme 

 has been printed and widely circulated, but as it may have 

 failed to reach some of the zoologists of the country, I have 

 been requested to state that all who are interested in zoology 

 and anxious to promote its progress will be welcome. 



Sydney J. Hickson, 



The Victoria University, Manchester, August 3. 



