October 17, 1907] 



NATURE 



625 



The Red Spot on Jlpitek. — Mr. St.inlcy Williams 

 publishes his observations of the Great Rid Spot during 

 the most recent opposition of Jupiter in No. 4202 of the 

 lUlronomischc Kaclinchtcn (p. 23, September 30). He 

 records the spot as being as faint as ever it was, and 

 the observing conditions, especially at the commencement 

 of the opposition, were very poor. The rotation period 

 satisfying the observations is gh. 55m. 42-275., from 594 

 rotations, and the longitude is 20°-87 + o°-23. 



.Mr. Williams directs attention to the abbreviated 

 rotation-period which obtained between the oppositions of 

 1905-6 and 1906-7 ; during the former it was 

 gh. 55m. 4i-46s., whilst in the interval it was 

 gh. 55m. 36-255. This difference is too groat to attribute 

 to errors of observation, and indicates a real change in 

 the spot's position. Observations lead to the conclusion 

 that this change of position is in some way due to the 

 large mass of dark material known as the Pyramid Spot, 

 or South Temperate Disturbance, for on three occasions 

 such changes of position have synchronised with the 

 passage of the Disturbance past the Red Spot. The 

 general discussion of a large number of observations of 

 this phenomenon may. as Mr. Williams suggests, throw 

 considerable light on the nature, and possibly the mass, of 

 the Red Spot. 



The Proper >toTiONS of Stars in the Cluster 

 Messier 92. — In No. 4165 of the Astronomische Nach- 

 richten, Dr. K. Bohlin compared some measures of the 

 stars in the cluster Messier 92, made on an astrographic 

 plate taken at Stockholm in i8q8, with those made by 

 Schullz at Upsala in 1873, and found discordances which 

 were attributed to proper motions during the intervening 

 twenty-five years. 



Prof. Barnard has had this cluster under observation, 

 with the 40-inch Yerkes refractor, for some time past, and 

 in No. 4202 of the same journal he discusses his observ- 

 ations with the view of testing the theory of proper 

 motions. A comparison of the three sets of measures 

 leads him to the conclusion that the existence of actual 

 proper motions is very doubtful, for the cases of agreement 

 are practically equal in number to those in which the 

 measures do not agree. In a second paper he compares 

 the definite measures made by Schultz of the stars in the 

 bright part of the cluster with those made bv himself, and 

 definitely expresses his confidence in the opinion that the 

 discordances are not due to proper motion, but rather to 

 the uncertainty of the measured oositions. The knowledge 

 th.-it such uncertainty existed led Prof. Barnard to under- 

 take visual micrometer measures of various clusters with 

 the 40-inch refractor, and he hopes to publish the results 

 of the work in the course of the next twelve months. 



The Dominion Observatory, Ottawa. — l-"rom notes in 

 the current Journal of the Royal .-Xstronomical Society 

 (Canada), vol. i.. No. 4, p. 264, July-.\ugust, it is evident 

 that valuable results may b'e expected' from" the' investi- 

 gations now being carried out at the Dominion Observ- 

 atory, Ottawa. The new spectrograph is performing very 

 satisfactorily, and with the one prism gives spectra of 

 first-type stais, in which HiS, H5, He, and Hy are 

 accurately measurable ; H7 was the only hydrogen line 

 usable on the earlier spectrograms. Seven spectroscopic 

 binaries are under regular observation, and. in addition to 

 the results already published for a Draconis and 1 Orionis, 

 it is hoped that the provisional elements of four other 

 binaries will soon be completed. A new method, a modifi- 

 cation of Hartmann's, has been applied to the reduction 

 of the plates with considerable .".ccuracy and a great saving 

 of labour. Experiments, having for their object the pro- 

 duction of a flatter field, are being carried out, and it is 

 hoped to obtain a field of 8°, instead of the 2° or 3° at 

 orcsent available. .\ 6-inch first-quality plane grating 

 has been supplied by Dr. Brashear for use with the 

 mlostat telescope in solar research. Dr. R. G. de Lurv, 

 Mr. R. M. Motherwell, and Mr. J. N. Tribble have been 

 appointed to the staff for work on solar research, micro- 

 meter observations, and radial-velocity determinations 

 respectively. 



The Perseid Meteors. — A watch for Pcrseids was kept 

 at Greenwich from August 10 to 13, but very few brilliant 



NO. I 98 I, VOL. 76] 



meteors were seen, the display, on the whole, being con- 

 sidered a very poor one. The actual numbers of meteors 

 bright enough to be plotted were twenty-seven on 

 .•\ugust 10-11, sixty-four on .August 11-12, and eight on 

 .'\ugust 12-13. t)n the last-named night clouds interfered 

 with the observations, but the other two nights were quite 

 cloudless i^Observatory, No. 387, p. 366, September). 



BOTA'NICAL CONGRESS AT DRESDEN. 



THE German Botanical Society has this September 

 celebrated its twenty-fifth anniversary at Dresden 

 under the presidency of Prof. Schwendener, who justly 

 emphasised the promptness of publication and value of the 

 contents of the society's journal. Owing possibly to the 

 wording of the invitation to members to contribute papers 

 to the meeting, only one communication was made, by 

 Dr. Winkler, on parthenogenesis in plants. The sarne 

 botanist aroused great interest, and a short but lively dis- 

 cussion, bv exhibiting a growing plant obtained by graft- 

 ing Solatium ttigrum with a tomato variety, and by 

 encouraging, to the e.Kclusion of other buds, a composite 

 bud, -arising at the point of contact and fusion of the two 

 plants. The resulting shoot shows, from node to node 

 upwards, especially well seen in the leaves, alternately, 

 right and left, the characteristics of each plant. 'I he term 

 "graft-bastard" proposed was objected to by many. No 

 doubt more will be heard of the specimen if it forms 

 flowers. Prof. Bower and Colonel Prain were elected 

 honorary members of the society. 



In the earlier part of the week (September 8-15) the 

 Society of .-Vpplied Botanists and that of the Systematists 

 held their meetings. The applied botanists were pre^nt 

 in force, and many important papers were read. The 

 society by resolution agreed to urge on the Government 

 the necessity of making better provision in many of the 

 technical colleges for botany in its various branches. A 

 few weeks previously the professors in the universities 

 and technical college's met to form a union, one object 

 of which is to secure greater freedom of action and less 

 Government interference, without, however, loss of Govern- 

 ment funds. , n f 1. 



Lie's finely illustrated account of the flora of the 

 Brazilian province of Bahia, Hiltner's soil-bacteria investi- 

 gations, and Lindner's beautiful mould cultuies, were out- 

 standing features of this part of the meeting. The 

 svstematists made a delightful excursion to the Bohemian 

 Mountains (Rollberg, S.c.) to compare their varied flora 

 with the more uniform flora of the Elbe sandstone. On 

 the basaltic Rollberg Asplcnium septcntrionale. Woodsia 

 Ilvcnsis. Ribes alpinum, Allium strictum, and many other 

 interesting alpines were obtained. 



In the following week the German Society for the 

 Advancement of Science and Medicine met also in 

 Dresden. The botanical section was strongly represented 

 under the presidency of Prof. Pfeffer, who contributed a 

 paper on sleep movement in plants, Wettstein one on 

 the phvlogeny of the angiosperm flower, Molisch one on 

 ultra-microscopic organisms, while Prof. Drude gave a 

 demonstration in the botanic garden of his cultural work 

 on Cucurbita Pepo. He showed a well-established hybrid 

 between C. Pepo and C. instititia, the fruit having the 

 mottled colour of the latter, the size and form of the 

 former. Throughout Prof. Drude and his assistants, Drs. 

 Schorler, Naumann, and Schwede, did everything possible 

 to ensure the comfort of visitors and the success of the 

 meetings. The forestry school and arboretum at Tharandt 

 were visited ; but, owing to sudden illness, Prof. Neger was 

 unfortunately absent. Nobbe's Seed Station, formerly at 

 Tharandt, is now at Dresden under Dr. Simon s direction. 

 The botanical garden at Dresden, though small, shows 

 nianv interesting features. There are groups illustrating 

 geographical distribution, e.g. plants characteristic of 

 South Africa, Australia, &c. The illustrative plants 

 throughout the garden are kept small to economise space. 

 Bv using differently coloured labels, the periods of intio- 

 duction into European cultivation of our garden plants 

 are indicated 



