6o 



NA TURE 



[No\ E.MBKR 2 1, I 901 



important national industry and that the establishment of various 

 other industries round the centres where these brown-coal beds 

 occur is only a question of time. 



From a paper by Signer S. Canniz7.aro in the Alii del 

 I.incei we gather that a movement is on foot in Italy for intro- 

 ducing the teaching of electrochemistry into the polytechnic 

 schools of that country, and that the question has arisen as to 

 whether this teaching should be placed in the hands of physicists 

 or of chemists. In his paper, Signor Cannizzaro quotes the 

 opinions of Octtel, Foerster, Lorenz, Lunge and Weber in 

 support of the opinion that the subject falls within the domain 

 of the chemist rather than that of the electrician. 



Two somewhat closely allied papers on Rontgen rays appear 

 in the Journal de Physique for November, one by M. L. 

 Benoist and the other by M. G. Sagnac. In the former the 

 author finds that the general laws of transparency of diliferent 

 kinds of matter for Kiintgen rays of different kinds can be 

 reduced to simple forms, a result which is far from being true 

 of other previously known forms of radiation. According to 

 these laws the transparency depends only on the absolute and 

 atomic weights, and it appears possible, when these data are 

 known, to calculate the transparency of any body, however 

 complex, for rays of given quality. On the other hand, the 

 laws may be also taken as the basis of a classification of the 

 rays themselves, and they suggest important applications to 

 practical radiography and chemical analysis. 



A NEW extensometer has been designed by Mr. H. T. Bovey 

 for determining the longitudinal extension or compression of 

 any given length of a horizontal beam loaded transversely. It 

 consists essentially of two parallel overlapping steel bars the oppo- 

 site ends of which rest by knife blades against two points on the 

 specimen to be measured. Between the faces of the two bars 

 is a small roller carrying a mirror. Any extension or compres- 

 sion of the specimen causes relative motion of the bars rotating 

 the roller through a small angle which is readily observed by 

 means of the mirror, the reading being effected by means of an 

 ordinary telescope with cross hairs. In Mr. Bovey 's paper, 

 which is published in the Transactions of the Royal Society of 

 Canada, experiments are described showing the variations in 

 the position of the neutral surface in wooden beams bent by 

 different loads. 



Some ten years ago the Berlin Meteorological Institute sup- 

 plied a large number of rain gauges to the various German 

 provinces with the view of supplementing the regular observing 

 stations and of investigating the rainfall conditions. The fourth 

 publication of this very useful series for the provinces of Branden- 

 burg and Pomerania has recently appeared, having been, like 

 the previous ones, ofiicially prepared by Prof. G. Hdlmann. 

 The tables contain the average yearly values for 269 stations, 

 and are very clearly represented on a map, showing by various 

 degrees of tinting the ditTerences of rainfall of various districts 

 for each 50 millimetres between 450 and 750 millimetres. The 

 mean annual value for the whole area is about 24 inches. The 

 mean daily maximum falls amount to I'oS inch, but the absolute 

 daily maxima reach from 28 to 36 inches, and occasionally 

 considerably higher. Heavy falls are much more frequent in the 

 inland districts than on the coasts, owing to the greater frequency 

 of thunderstorms in the former localities. The longest periods 

 of drought are about thirty days on the coast and forty days 

 inland, and the longest wet periods from twenty-five to thirty 

 days. These valuable discussions may well serve as patterns for 

 such investigations ; they are beautifully printed, and issued at 

 the low price of one mark. 



In this country- we do not take much note of insect pests 

 which damage violets, but this is not the case in the United 

 NO. 1673, VOL. 65] 



States, where large quantites of these flowers are gnnvn under- 

 glass for commercial purposes. In Bulletin No. 27 of the 

 Entomological Division of the U.S. Department of Agriculture, 

 Mr. F. H. Chittenden describes a long list of insects deleterious 

 to violets, roses and other garden plants. In the case of the 

 violet, the worst appears to be the so-called " greenhouse leaf- 

 Iyer," which is the caterpillar of the moth Phfyclaenia (or, as 

 Sir G. F. Ilampson calls it, Pioraca) rubigatis, which eats 

 away large patches from the under side of the leaves. English 

 horticulturists are familiar with a closely allied species, P. 

 feriugalis. Various remedies are suggested for the ravages of 

 these and other pests. 



A SHORT time ago mention was made in these notes of a 

 paper by Mr. J. ]. Wilkinson on the pharynx of the " rat-tailed 

 maggot," the larva of the fly Eristalis. To the last issue (vol. 

 Ixx. part 2) of the Zeitschrift fiir Wiss. Zool., Dr. B. Wahl, of 

 Graz, contributes an important memoir on the development of 

 the hypodermal tissues of the imago in the same larva. In the 

 same journal, Ilerr G. Rottmann publishes the first part of the 

 results of his investigations into the development of the lingual 

 ribbon, or radula, of the Mollusca, this part dealing with the 

 cephalopods. Special interest attaches to his account of the 

 growth and replacement of the teeth with which the radula is 

 studded, the process being rendered clear by means of several 

 figures in the text. A third article, by Dr. O. Maas, deals with 

 the reproductive process in the sponges of the genus Tethya, 

 which, as is well known, diflfer from all other members of the 

 group in taking place by means of germinal buds. In another 

 communication Dr. E. Wasmann completes his account of the 

 parasitic flies recently discovered inhabiting the nests of white 

 ants and named Termitoxenia. 



The Monthly Review for November contains an extremely 

 interesting and well-illustrated article, by Mr. T. A. Cook, on 

 the modern thoroughbred, dealing both with its history and its 

 future prospects. From the evidence of contemporary docu- 

 ments, the author shows that the English horse previous to the 

 introduction of the first strain of Arab blood must have been an 

 animal endowed both with speed and endurance, and it was 

 evidently one specially fitted to benefit by the cross in question, 

 which has resulted, through a long and puzzling process, in the 

 evolution of our present thoroughbred stock. Some attempts 

 have been made to show that, because all the pedigrees of 

 this stock can be traced back to Arab sires, the English 

 thoroughbred is the product of Eastern blood alone, but this 

 the author shows to be an untenable view. After noting the 

 marked increase in the size of thoroughbreds since the date of 

 the infusion of the Arab strain, Mr. Cook proceeds to inquire 

 whether short-course twoyear-old racing has had a deleterious 

 effect on the endurance and stamina of the breed. On the whole, 

 his conclusions with regard to this point are reassuring, and he 

 notes with satisfaction a tendency at the present day to revert to 

 long-distance racing. Should English thoroughbreds require 

 fresh blood, the Arab strain at the present day would be useless, 

 and it is considered that Australian and New Zealand sires 

 would be most suitable for this purpose. Much stress is laid on 

 the importance of preserving good portraits, and if possible 

 models, of our best thoroughbreds; and it is suggested that when 

 equestrian statues are made a well-known horse should be 

 modelled. It is mentioned that in the statue of Charles I. at 

 Charing Cross the charger is a model of a "great horse" from 

 his Majesty's stables. The article concludes with some observa- 

 tions as to the best conventional mode of drawing running 

 horses. 



From Queensland we have received the Annual Progress 

 Report of the Geological Survey for 1900, by Mr. W. H. 

 Rands, Government Geologist, together with several detailed 



