588 



NATURE 



{April 1 8. 18S9 



Trans. Entom. Soc, April 1884, August 1S85, and June 18S6 ; 

 I'roc. koy. Soc, No. 237, 1885, and No. 243, 1886; "The 

 Experimental Proof of the Protective Value of Colour and 

 Markings in Insects in reference to their Vertebrate Enemies " 

 (Proc. Zool. Soc, 1887); "An Inquiry into the Cause and Extent 

 of a special colour-relation between certain exposed Lepidopterous 

 Pupse and the surfaces which immediately surround them " (Phil. 

 Trans., 1887); "Notes in 1886 on Lepidopterous Larvjc" 

 (Trans. Entom. Soc, 1887). 



William Johnson Sollas, D.Sc (Cantab.), Hon. 



LL.D. (Dubl.) 

 F.R.S.E., F.G.S. Late Fellow of St. John's College, Cam- 

 bridge. Professor of Geology in the University of Dublin. 

 Author of numerous papers on Geology, Paleontology, .and the 

 Natural History of the Sponges, among which the following 

 maybe specially enumerated: — "On the Silurian District of 

 Khymney, tScc" (Quart. Journ. Geol. Soc, vol. xxxv. p. 475); 

 "On a New Species of Plesiosaurus, &c." {ibid., vol. xxxvii. 

 p. 440); "On the Structure and Affinities of the Genus 

 Siphonia {ibid., vol. xxxiii. p. 242); "On Staiironema, a New 

 Genus of Fossil Hexactinellid Sponges " {Ann. and Mag. Nat. 

 Hist., Ser. 4, vol. xix. p. i.) ; "On the Flint Nodules of the 

 Trimmingham Chalk" {ibid., Ser. 5, vol. vi. p. 384); "On 

 the Sponge Fauna of Norway" {ibid., Ser. 5, vol. v. p. 130, 

 5 parts), 



Charles Todd, M.A. (Camb.), C.M.G., 

 F.R.A.S. Postmaster-General, Superintendent of Telegraphs, 

 and Government Astronomer. He has executed important 

 astronomical observations extending over thirty-eight years, 

 including Transit of Venus, Jupiter's Satellites, Deter- 

 mination of Australian Longitudes, &c. He has conducted 

 Meteorological Observations in South Australia extending 

 over thirty years. He has written a Treatise on the Meteoro- 

 logy of S )uth Australia, and other works. He has con- 

 tributed papers to the Royal Society of South Australia, and was 

 responsible for the erection of the telegraph line across the in- 

 terior of Australia froji Adelaide to Port Darwin, 2000 miles in 

 length, and to Western Australia, looo miles in length. 



Herbert Tomlinson, B.A. (Oxford), 

 Formerly Junior Student of Christ Church, Oxford. Whit- 

 worth Exhibitioner, 1870. Demonstrator of Natural Philo- 

 sophy in King's College, London. Author of numerous 

 papers on physical subjects published in the Phil. Trans., 

 Proc. Roy. Soc, Phil. Mag., &c., the most important of 

 which relate to the influence of stress and strain on the Physical 

 Properties of Matter. The following may be enumerated :— 

 (i) "Effect of Magnetization on the Electrical Conductivity of 

 Iron" (Proc. Roy. Soc, 1875) ; (2) "Increase in Resistance to 

 the passage of an Electrical Current produced in certain wires 

 by Stretching" (Hid., 1877) ; (3) "Alteration of Thermal Con- 

 ductivity of Iron and Steel caused by Magnetism" {ibid., 1878). 

 The following papers relate to the influence of Stress and Strain, 

 &c :— (4) "Moduli of Elasticity "(Phil. Trans., 1883); (5) 

 "Electrical Conductivity" {ibid. ) ; (6) " Relations between Moduli 

 of Elasticity, Thermal Capacity, and other Physical Constants" 

 (Proc Roy. Soc, 1885); (7) "Alteration of the Electrical Con- 

 ductivity of Cobalt, &c, by Longitudinal Traction" (Proc Roy. 

 Soc, 1885); (8) "Internal Friction of Metals" (Phil. Trans., 

 1886); (9) "Co-efficient of Viscosity of Air" (//^eV/.) ; (10) "On 

 Certain Sources of Error in Connection with Experiments on 

 Torsional Vibrations " (/%?■/. Mag., 1885); (11) "Temporary 

 and Permanent Effects on some of the Physical Properties of 

 Iron produced by raising the Temperature to 100° C. " {ibid., 

 1886) ; (12) " Effect of Change of Temperature on the Internal 

 Friction and Torsional Elasticity of Metals " (abstr. in Proc. Roy. 

 Soc, 1886); (13) "Effect on Magnetization on the Elasticity 

 and the Internal Friction of Metals" (Phil. Trans., vol. clxxix. 

 p. l); and other papers. 



Gerald F. Yeo, M.D. (Dubl.), 

 F.R.C.S. Professor of Physiology, King's College, London. 

 Researches :—" On the Physiology of the Central Nervous 

 System " (with Prof. Ferrier) (Proc Roy. Soc, 1881 ; Phil. 

 Trans., 1884); "On the Physiology of Muscle and Nerve" 

 (with Dr. Cash) (Proc. Royal Soc, 1882 and 1883 ; Journal of 

 Physiol., 1884); (with Mr. Herroun) {ibid., 1884); "On the 



Composition of Human Bile" (with Mr. Herroun) (Journ. of 

 Physiol., 1884); "On the Cau e of the First Sound of the 

 Heart" (with Dr. Barrett) {ibid., 1884). On Pathological 

 Subjects: — "Diseases of the Kidney" (Dubl. Path. Soc, 

 1865); "Lymph Glands" {Afed. Jdhrb. d. Aertze, in Wien, 

 1871) ; " Pleuropneumonia in Cattle" (Report for Roy. Agric 

 Soc, 1878) ; and of numerous other papers (Proc. Dubl. Path. 

 Soc. ; Iris/i Hospital Gazette; Dubl. Journ. Med. Sci., 1872 to 

 187s). Author of " Manual of Physiology." 



THE SHOOTING-STARS OF APRIL. 

 T N recent years this meteor group has not developed 

 •^ exceptional activity, nor have its annual returns 

 attracted such general observation as the Perseids 

 of August ; but it is nevertheless a stream that is 

 entitled to a considerable amount of interest, as some 

 of its displays appear to have been noticed in ancient 

 times, and it is identified with the comet described 

 by Thatcher on April 4, i86r. The modern displays of 

 this shower have not justified the anticipations formed of 

 it in regard to its richness because of its periodic cha- 

 racter. Of late years the special region of the orbit 

 where the meteorites are clustered in the richest pro- 

 fusion has probably been far removed from the earth. 

 The apparent feebleness of the shower may therefore be 

 regarded as merely temporary. The Leonids of November 

 have during the last fifteen years similarly offered a poor 

 spectacle to those who have encouraged the hope that 

 they might attain a prominent degree of activity. But 

 with the parent comet (I. 1866), in distant parts of its 

 path, it is not surprising that comparatively very few of 

 these meteors have been seen. The same remark equally 

 applies to the April meteors. They are chiefly condensed 

 near the comet of 1861, which is now traversing a section 

 of its orbit sufficiently remote from the earth to have 

 withdrawn all the richer parts of the stream from our 

 cognizance. The meteorites lately encountered by the 

 earth upon crossing the node of this comet on about 

 April 20 are simply the outlying and more scattered 

 remnants of the system. It is highly probable, however, 

 that the distribution of the particles is to some extent 

 irregular, and that in certain years the shower attains a 

 more pronounced aspect than the conditions would indi- 

 cate. Thus in 1884 there was a rather conspicuous dis- 

 play, the number of meteors visible being about 22 per 

 hour for one observer ; but this, though representing a 

 striking degree of productiveness relatively to the minor 

 showers, yet falls much below the character of a meteor- 

 stream of first-class importance. 



In the present year, the Lyrid showers, if visible, will 

 be most favourably witnessed in the early part of the 

 night, as moonlight will interfere in the morning hours. 

 On April 19 the moon rises at iih. 53m., on the 20th at 

 I3h., and on the 21st at I3h. 55m. The north-eastern 

 sky should be M'atched before our satellite emerges from 

 the horizon. The most essential features to be noticed 

 during the progress of the display will be the following : — 



(i) The position of the radiant-point on each night of 

 observation. It is very important to note whether this 

 point becomes rapidly displaced to the eastwards, as in 

 1885 (Nature, vol. xxxii. p. 5). 



(2) The horary number of meteors appearing to one 

 observer, and the proportion radiating from Lyra. 



(3) The paths and visible peculiarities of the largest 

 meteors. It is necessary that such data be gathered and 

 utilized in computations of the real paths of those meteors 

 which may be recorded at more than one station. 



(4) The duration of the individual meteor-flights. This 

 is an element extremely difficult to estimate with tolerable 

 precision, especially in respect of swift-moving meteors 

 like the Lyrids. 



(5) The positions of radiants of the minor streams 

 which furnish meteors at this epoch. Subjoined are the 



