214 



NATURE 



[August i8, 1910 



alone or photographic rays alone, he photographed the star 

 with short exposures, taking a large number of photo- 

 graphs in quick succession, and from these he subsequently 

 reduced the times of the photographic and visual minima 

 respectively. The results first obtained showed a time- 

 difference of six minutes, on the average, between the two 

 divisions of radiations. But this difference was in the 

 opposite direction to that found by the earlier observers : 

 that is to say, the visual rays were " retarded" more than 

 the optical. 



A subsequent revision and refinement of the data con- 

 fumed this result qualitatively, but slightly reduced the 

 time-difference {MiUeihmgen dcr Nikolai-Hauptstemwarte 

 tu Pulkowo, vol. iii.. No. 31, 1910). 



Anomalous Scattering of Light. — No. s. vol. xxxi., of 

 the Astrophysical Journal contains an important paper in 

 which Dr. Julius upholds his hypothesis as to the causes 

 which produce the unequal distribution of light over the 

 sun's disc, as shown on spectroheliograms. He states that 

 the results so far obtained are no less favourable to the 

 anomalous-dispersion theory tlian they are to that hypo- 

 thesis which ascribes the variable illumination to absorp- 

 tion effects, and proceeds to support his statement by the 

 discussion of the several phenomena. 



Dr. Julius also defines his terms more rigorously than 

 in former papers. " Anomalous dispersion " is reserved 

 for the general property of matter, that its refracting 

 power varies rapidly in the neighbourhood of an absorp- 

 tion line. Previously this term was used indiscriminately 

 with " anomalous refraction " ; but the latter is now to be 

 used exclusively for the irregular phenomena with which 

 Dr. Julius deals in all his papers; "anomalous scatter- 

 ing " is also introduced, and is shown to be an active 

 agent in modifying various effects. 



The Spiral Nebula M51 (Canum Venaticorum). — As 

 nn extract from the Rivista di Astronomia (Turin), we 

 have received a paper in which Madame Dorothea Isaac- 

 Roberts discusses in detail the numerous condensations, 

 spires, &c., shown on Dr. Roberts's photograph of the 

 spiral nebula M51 Canum Venaticorum. Each feature is 

 described, and the position-angles, distances, &c., are given, 

 so that any future worker may determine, witli a mini- 

 mum of labour, whether or not any variation has taken 

 Tjlace since the epoch when Dr. Roberts's photograph was 

 Taken. Madame Roberts also shows that the present form 

 "indicates a process of evolution which has led, and will 

 ■orobably lead, to the partition of this remarkable object 

 into secondary nebulae and condensations. 



SupPLE.MENT to the " ASTRONOMISCHE Nachrichten. " — 

 AVe have received, as a supplement to the Astronnmische 

 Nachrichten, No. 17 of the Astronomische Abhandlungen, 

 edited by Dr. Kobold. Among its six articles, it contains 

 papers dealing with an experimental research on phase 

 action in regard to heavenly bodies, a new explanation of 

 the origin of comets, and a description by Prof. Lowell 

 of the new canals discovered on Mars. The price of the 

 supplement is 3 marks. 



THE FIRST INTERNATIONAL CONGRESS OF 



ENTOMOLOGY. 

 T^HE first International Congress of Entomology was 

 ^ held at Brussels on August 1-6. The establishment 

 of the congress was in great measure due to the initiative 

 of Dr. Karl Jordan, of Tring, whose tact and energy have 

 throughout contributed largely to the success of the under- 

 taking. Having, in the iirst place, secured the support 

 of leading entomologists in this country and abroad. Dr. 

 Jordan organised, in the course of last year, a series of 

 preliminary meetings in London, which were attended by 

 Dr. Horn, of Berlin, M. Janet, of Paris, Prof. Poulton, 

 F.R.S., of Oxford, and others, under the chairmanship of 

 Dr. F. A. Dixpy, F.R.S., president of the Entomological 

 Society of London. At these meetings it was arranged 

 that tile first congress should be held at Brussels in 19 10, 

 and local secretaries were appointed to promote the interests 

 of the movement in all countries of the civilised world. 

 So well did these representatives perform their part, that 

 no fewer than 292 entomologists assembled in Brussels 

 for the opening of the congress. 



NO. 2129, VOL. 84] 



Proceedings began on tlie evening of July 31 with an 

 informal reception by Prof. Lameere (who, as president of 

 the Ento.mological Society of Belgium, had been invited to 

 preside over the congress) and the other members of the 

 Belgian society. The gathering was highly enjoyable from 

 the social point of view, and gave acceptable opportunities 

 to entomologists from other parts of the world for making 

 each other's personal acquaintance. 



On August I the official proceedings were opened by 

 Prof. Lameere in the Salle des Fetes, a large building 

 within the precincts of the exhibition, the use of which 

 for the general and sectional meetings of the congress had 

 been liberally granted by the authorities. His address of 

 welcome to the delegates and other members of the con- 

 gress included an eloquent vindication of the claims of 

 entomology to serious attention, both as a science and 

 also as a study having practical bearings of the highest 

 importance. The address, which was well received, was 

 followed by the reading of a report by the secretary of the 

 congress, M. Severin, on whose shoulders the chief labour 

 of organisation had fallen. After the conclusion of the 

 more formal proceedings, the congress turned to the 

 regular business of entomological communcations. Some 

 of the most interesting items on the programme bore refer- 

 ence to subjects of economic importance. Prof. Theobald 

 (Wye) had a paper on the artificial distribution of insect 

 pests, and M. Andres (.Alexandria) contributed notes on the 

 lepidopterous enemies of the cotton-crop. Dr. R. Stewart 

 MacDougall (Edinburgh) discoursed on the beetle 

 Galerucetla Uiieola, so destructive to the Midland osier- 

 beds, and Sir Daniel Morris, formerly director of the 

 Imperial Department of Agriculture in the West Indies, 

 gave a graphic account of the progress of economic 

 entomology in the West Indies and in India, to which 

 progress, it may be noted. Sir Daniel's own efforts have 

 very largely contributed. Among other items of interest 

 were communications from Prof. Kolbe (Berlin) on the 

 comparative anatomy of the Coleoptera, and from MM. 

 Janet (Paris), Speiser (Sierakowitz), and Lyman (Montreal) 

 on various points connected with classification. 



The proceedings on August 2 opened with a luminous 

 and admirably delivered discourse by M. Blanchard 

 (Paris) on medical entomology. The eloquence of the 

 lecturer, and the vast importance of the subjects with 

 which he dealt — malaria, yellow fever, and the sleeping 

 sickness, all of which are directly dependent for their 

 spread on the agency of insects — made a great impression 

 on his audience. The day's programme also included an 

 excellent lecture by Father Wasmann on ants and their 

 guests, illustrated by lantern-slides ; communications by 

 Prof. Theobald on the distribution of the yellow-fever 

 mosquito, Stegomyia fasciata; by Prof. Carpenter (Dublin) 

 on tlie warble-flies ; and others of equal interest. 



The business on August 3 was largely taken up with 

 the subject of mimicry and its bearing on evolution. The 

 proceedings began with the delivery of a discourse by 

 Dr. F. A. Dixey, F.R.S. (Oxford), on the general subject 

 of insect mimicry. The lecture, which was plentifully 

 illustrated by laiitern-slides, directed especial attention to 

 the ascertained data of mimicry in relation to affinity and 

 to sexual, seasonal, and geographical conditions. Various 

 suggested explanations of the phenomena were discussed 

 in "the course of the lecture, and the opinion was advanced 

 that natural selection afforded the only reasonable inter- 

 pretation of the facts at present within the knowledge of 

 entomologists. Special aspects of the subject were after- 

 wards dealt with by Dr. Karl Jordan (Tring) and Prof. 

 Poulton, F.R.S. (Oxford), the former exhibiting an 

 interesting series of lantern illustrations, and the latter 

 showing a wonderful series of models and mimics captured 

 at the same time and place by Mr. Wiggins in Uganda. 

 A note of scepticism was struck by Mr. Schaus, who, on 

 the strength of many years' observation in the neotropical 

 region, was disposed to deny that mimicry was of any 

 service to the insects exhibiting it. A lucid exposition of 

 Mendelism as applied to the Lepidoptera was given by 

 Prof. Punnett (Cambridge), and an interesting account 

 of his experiments on the influence of temperature on 

 seasonallv dimorphic moths was contributed by Mr. F. 

 Merrifield (Brighton). 



On August 4 much interest was excited by Mr. Donis- 



