296 



NATURE 



[December 29, 1910 



Manchester. 



Literary and Philosophical Society, November 15, — 

 Mr. Francis Jones, president, in the chair. — Dr. W. 

 Makower and Dr. S. Rubs : Note on scattering during 

 radio-active recoil. During experiments on the recoil of 

 radium B from radium A, not only did a surface directly 

 exposed to the recoil stream become active, but surfaces 

 situated outside the direct stream also received active 

 deposit. It was thought that these effects were due to 

 scattering from the surfaces upon which the recoil atoms 

 fell, and experiments were made to test this. These 

 were carried out in a high vacuum, and a plate was 

 mounted in such a way that it was outside the recoil 

 stream coming from an active wire coated with radium A, 

 but so that recoi) atoms scattered from a copper reflector 

 could reach it. When the plate was examined it was 

 found to be active, and by measuring its rate of decay 

 with an a-ray electroscope, more than half of the active 

 matter proved to be radium C, and not radium B. This 

 result can be explained if, when the radium B impinges 

 on the reflector, a small portion of it is scattered on to 

 the plate, but the greater part remains on the reflector 

 and subsequently gives rise to radium C, a small fraction 

 of which is then directly projected on to the plate. — 

 D. M. S. Watson : Upper Liassic Reptilia. Part iii. : 

 Microcleidus and on the genus Colymbosaurus. 



November 29. — Mr. Francis Jones, president, in the 

 chair. — Prof. A. Schwartz and Philip Kemp : Some 

 physical properties of rubber. Pure rubber strip which 

 has not previously been extended has a large coefficient 

 of linear expansion when tested under loads just sufficient 

 to keep the strip straight. The behaviour of rubber when 

 heated under tension was found to be more complex than 

 had previously been supposed. The previous history of the 

 rubber as to whether it has been previously extended or 

 not largely affects the result. The modulus of elasticity 

 of the rubber probably changes with load and tempera- 

 ture. Considerable change takes place in pure rubber 

 when rested in air for some time at normal temperatures, 

 the strips, which were originally translucent and flexible, 

 becoming opaque and hard. An opaque, hard, and com- 

 paratively inextensible condition can be obtained by slightly 

 warming a pure rubber strip and rapidly extending it as 

 far as possible by hand. On keeping it extended thus for 

 a few seconds and then removing the tension it will be 

 found that the rubber remains extended in an opaque 

 condition, but can be brought back to its original 

 dimensions and condition by the application of slight heat. 

 The mecHanical hysteresis of rubber has been studied and 

 applied to the testing of rubber. The hysteresis machine 

 was described. A test-piece of rubber, subjected to a 

 series of complete cycles of extension and retraction, was 

 shown to increase in length, according to a logarithmic 

 law, with respect to the numbers of the cycles. The 

 slow stretch of rubber under a constant load also follows 

 a logarithmic law with respect to time. The work done 

 in extension, in retraction, and in the rubber itself, was 

 shown to be proportional to the cross-sectional areas of 

 the specimens. 



Dublin. 



Royal Irish Academy, December 12.— Dr. F. A. Tarleton 

 president, in the chair. — G. H. Pethybridgre and Paul A. 

 Murphy : A bacterial disease of the potato plant in 

 Ireland, and the organism causing it. The authors 

 describe a bacterial disease of the potato plant of frequent 

 occurrence in Ireland, and give an account of the organism 

 which they isolated from diseased plants, and with which 

 successful inoculations were carried out on healthy plants 

 and tubers. It is a multiflagellate peritrichous bacillus, 

 liquefying gelatine and producing decay in the living 

 tissues of a variety of plants in addition to the potato. 

 It resembles in many respects other organisms which have 

 been found causing similar diseases in potatoes both in 

 the Old and New Worlds, but does not appear to be 

 identical with any of them. The name Bacillus melano- 

 genus is proposed for it. — A. W. Stelfox and Robert 

 Welch : A list of the land and fresh-water Mollusca of 

 Ireland. In the introduction the authors give a short 

 risumi of the work which has been done in this branch 

 of natural history in Ireland from the time of Captain 

 Thomas Brown to the present day. This includes a list 

 of species added to the Irish molluscan fauna since the 



NO, 2148, VOL. 85] 



publication of Dr. Scharff's valuable work in 1892. The 

 paper is divided into three parts ; first comes the list 

 proper, which includes only bona fide records, i.e. records 

 which are backed up by specimens ; secondly, a list of 

 doubtful and erroneous records ; and, lastly, a complete 

 list of all species which are known to have been intro- 

 duced into Ireland in recent years. These are mainly 

 confined to greenhouses and nursery gardens. In the 

 list proper the authors give notes on the principal 

 variation of many of the species, especially that variation 

 which tends to be of interest to those who study the 

 geographical distribution of plants and animals. A full 

 bibliography accompanies the paper. — H. Wallis Kew : A 

 synopsis of the false scorpions of Britain and Ireland. The 

 arachnidan order Pseudoscorpiones is represented in the 

 British Islands by twenty-two species, one of which, un- 

 known in Britain, is confined in Ireland to the extreme 

 south-west. 



DIARY OF SOCIETIES. 



MONDAY, January 2. 



Aristotelian Society, at 8.— The Standpoint of Psychology : Benjamin 

 Dumville. 



Society of Chemical Industry, at 8.— The Determination of Sucrose 

 (Cane Sugar) in Sugar Factory Products by Clerget's Process using 

 Invertase as Hydrolyst : J. P. Ogilvie.— The Testing of Incandescent 

 Mantles : J. H. Coste and W. E. F. Powney.— Radiation Errors in Flow 

 Calorimeters : J. H. Coste and B. R. James. 



THURSDAY, January 5. 



R8NTGEN Society, at 8.15.— The Radioactivity of Thorium : Prof. 

 Rutherford. 



CONTENTS. PAGE 



Malaria Prevention. By W. B. L 263 



The British Museum Collection of Fossil Reptiles. 



By R. L 264 



Electro-Cardiograms. By Prof, John G. McKen- 



drick, F,R.S 265 



Australian Tribes 267 



Some Critical Species of Veronica. By A. B. R, . 267 



School Drawing 268 



Our Book Shelf 268 



Letters to the Editor:— 



.\ Biological Inquiry into the Nature of Melanism in 



Amphidasis betularia, Linn. — H, S. Leigh , . . 270 

 Protection from "White Ants" and other Pests. — 



Will, A. Dixon . . 271 



January Meteors. — ^John R. Henry 271 



Excavations in Crete, {Illustrated.) By H. R, Hall 272 



The Lead Glaze Question 273 



The New Encyclopaedia of Sport. {Illustrated.) By 



R. L 274 



Western China. {Illustrated.) By J. T 275 



The Calorimetry of Man. By Prof. J. S, Mac- 



donald 276 



Notes 277 



Our Astronomical Column : — 



The Spectrum of the America Nebula ....... 282 



The Movements of Certain Stars, in Space, Compared 



with that of the Sun 282 



The Italian Observatoiies 282 



Astronomy at the Brussels Exhibition 282 



Tracing the Solar Corona in Lunar Observations . . 283 



Annual Publications . . 283 



American Hydrography. {Illustrated.) By B, C. . 283 



Palaeontological Papers. By G. A. J. C 284 



A Monograph of the Jelly fishes. {Illustrated.) . . 285 



Measures of the Solar Parallax 287 



American Vertebrate Palaeontology 287 



The Influence of River Systems in the East ... 2J 

 Recent Progress in Electric Lighting. By Prof. 



E. W. Marchant 2i 



Smoke and its Prevention. By Prof. Vivian B. 



Lewes 290 



University and Educational Intelligence 294 



Societies and Academies 295 



I Diary of Societies 296 



