August i6, 1906] 



NA TURE 



385 



ill 1905, !s a translation of the original account of tlic dis- 

 ciivt-ry and transport to St. Petersburg of tlie now well- 

 linuwn Berezovka mammoth. In discussing whiteness in 

 .animals in the second paper, the author lalves occasion to 

 dissent from the view that British parli-cattle are albinos, 

 urgiiig as a reason that they have been white for centuries 

 — an argument which has, of course, no value at a: . 



.According to the Irish Naturalist for August, the bog- 

 slide at Ballycumber, King's County, in June last, of 

 which much was made in the Dublin papers, was a very 

 insignificant affair. To the same issue Mr. R. Southern 

 contributes notes on Irish oligochsetous worms of the genus 

 Enchytraeus, recording three species new to the Irish 

 f.'uma. one of which appears to be also new to science. 



Paut vii. of the " Fauna of New England," issued as 

 .in Occasional Taper of the Boston Society of Natural 

 History, consists of a list of the ants (Formicidic), by 

 Ml-. W. M. Wheeler. 



The vexed question of the chemical nature of thorium 

 and the origin of its radio-activity forms the .subject of a 

 series of papers in the American Journal of Science (vol. 

 .\xi.. No. 126). Dr. Bertram Boltwood has determined the 

 amount of o-ray activity due to thorium in different 

 minerals, containing, in addition to thorium, other radio- 

 active constituents. The values obtained clearly indicate 

 that this activity per gram of thorium is a constant in- 

 dipondent of the nature of the mineral. The total activity 

 of minerals containing thorium and uranium can, indeed, 

 be calculated from the proportions in the mineral of these 

 elements. The constancy of the " specific activity " of 

 thorium in different minerals is in support of the view 

 that Hahn's radio-thorium is a degradation product of 

 thorium itself; the transformation of thorium into radio- 

 thorium is probably rayless. It is a remarkable fact, how- 

 ever, that the specific activity of thorium in samples of 

 thorium nitrate and oxide prepared on the commercial scale 

 for the Welsbach mantles is only about half that of 

 thorium in the same substances prepared directly from the 

 minerals worked with. This is explained by assuming that 

 the commercial method of purifying thorium salts is re- 

 markably efficient in separating radio-thorium, the change 

 of thorium into radio-thorium occurring only very slowly, 

 .'limilar conclusions were arrived at by Mr. H. M. 

 Dadourian and by Messrs. McCoy and Ross from experi- 

 ments of a somewhat different character described in the 

 same number. The question whether thorium can be 

 obtained entirely free from radio-thorium and completely 

 inactive is, however, still unsettled. 



The July number of the Journal of the Rontgen Society 

 contains an address by Mr. Frederick Soddy on the nature 

 of the o ray. A clear account of recent investigations and 

 hypotheses is given with regard to this problem, and the 

 author, in addition, briefly refers to some experiments he 

 has made to ascertain whether the o particle is capable of 

 deviation in a magnetic field under conditions in which 

 it has not suffered impact with a single gas molecule ; but 

 the results would indicate that in the highest vacuum 

 obtainable the a rays are deflected as readily as in ordinary 

 air. In the American Journal of Science for July Mr. M. 

 Levin shows that polonium is a homogeneous source of 

 o rays, and that the range of the a particle in air is 

 3..SI) cm., being slightly greater than that of the a particle 

 of radium (3-50 cm.), but less than that of the a rays of 

 r.idium C (range 7'06 cm.). 



NO. 1920, VOL. 74] 



.An interesting note on the fluorescence of anthracene 

 v.ipour is published by Mr. T. S. Elston in No. 4 of the 

 Johns Hopkins University Circular. It is concluded that 

 the light exciting the fluorescence has a wave-length of 

 about 390 ii/i, and that the fluorescence spectrum extends 

 continuously from X = 36s /i/i to X = 470 (i/*, showing three 

 distinct bands at wave-lengths 390, 415, and 432 /i/i. It 

 is clear that for anthracene vapour Stokes's law, which 

 states that fluorescence lies entirely on the red side of the 

 exciting light, does not hold. 



A SCIENTIFIC and not too technical exposition of the 

 present position of certain problems connected with heredity 

 will be found in Naturwissenschaftliche Wochenschrift 

 (July i) in an article written by Dr. E. Teichmann. The 

 first part of the article is devoted to a review of the hypo- 

 theses and facts adduced in recent papers by Heider, 

 Correns, and Strasburger in favour of regarding the 

 chromosomes as bearers of hereditary characters, and show- 

 ing how the chromosome divisions fit in with Mendelian 

 principles ; this part is illustrated with useful explanatory 

 diagrammatic figures. Dr. Teichmann then gives a short 

 account of the hypothesis advanced by Dr. Hatschek, who 

 interprets heredity as a chemical process. Hatschek postu- 

 lates generative molecules occurring in the nuclei, and 

 energy molecules in the cells ; it is by changes in the 

 generative molecules of the reproductive cells that variations 

 are produced. Reference is also made to Loeb's latest 

 expression of opinion, in which he also favours a chemico- 

 physical explanation. 



In the course of a lecture addressed to the Field 

 Naturalists' Club of Victoria, and published in the 

 Victorian Naturalist (June), Mr. D. McAlpine summarises 

 a few of the interesting points observed in studying the 

 plant rusts in Victoria. The geographical distribution of 

 some of the species furnishes curious facts. The genus 

 Uromycladium causing " witches-broom," and character- 

 ised by the production of a colourless cyst along with one 

 or two spores, is only known from Java outside Australia. 

 An aecidium on wallaby grass has only been found else- 

 where on a species of Stipa in the Argentine, Chili, and 

 California. The absence of any native barberry plants 

 would suggest that wheat rusts in Australia forgo a 

 hetercecious existence, and it was found that the spores 

 would not even infect imported plants. 



The third and concluding portion of Sir Joseph Hooker's 

 enumeration of British Indian species of Impatiens, pub- 

 lished as vol. iv., No. 3, of the Records of the Botanical 

 Survey of India, contains the list of known species for the 

 Western Peninsula, also for Ceylon and Malaya. The 

 Peninsular balsams differ in sectional characters from the 

 Himalayan and Burmese ; they all fall into the short- 

 capsuled group, and none possesses the two additional 

 lateral sepals ; many are endemic, only three being found in 

 northern or eastern India, and one of these is the poly- 

 morphic Impatiens balsamina. There is some affinity 

 between the Malabar and Ceylon species, although the 

 majority of the latter are endemic. In marked contrast to 

 the large number of balsams from Burma, only seven 

 Malayan species are recorded, and none of these is found 

 in Burma. Impatiens mirabilis, that is only known from 

 one island, is a remarkable species, as it produces a branch- 

 ing stem 5 feet high and 22 inches in diameter, bearing 

 leaves 6 inches to 10 inches in length. 



.\s recent research has led to the transference of many 

 of the so-called fossil ferns of the Carboniferous period to 

 the pteridosperms, and has thrown doubt on others, it is a 



