NATURE 



\May 



[< 



His first publication of importance was entitled " Grundziige 

 einer allgemeinen Photometrie des Himmels" (1S61), and in 

 1865 followed the work, which must be considered his principal 

 one, " Photometrische Untersuchungen niit besonderer Rticksicht 

 auf die pbysische Bcschaffenheit der Himmelskbrper " (Leipzig, 

 Engelmann). The photometer constructed by Zollner compares 

 the light of the celestial object observed with an artificial star 

 produced by a constant source of light (the flame of a para fiin 

 lamp kept at a constant height), which can be varied at will by 

 turning two of the three NicoL through which the light from 

 the flame has to pass. A crystal plate allows of variation of 

 colour. With this instrument Zollner observed both the moon, 

 the principal planets, and the fixed stars, and the last chapter of 

 his " Untersuchungen " contains an interesting attempt to explain 

 all the various phenomena of variable stars, sun-spots, &c, by 

 the gradual cooling of all the celestial bodies. In several ta;e,- 

 papers in the Proceedings [Beriehte) of the Saxon Society of 

 Sciences these ideas are further developed, particularly with 

 respect to the nature and periodicity of sun-spots. Without 

 liaowing it Zollner here followed in the footsteps of Buffon. 

 Zollner next directed his attention to spectrum analysis, and on 

 February 6, 1869, he read a paper before the Saxon Society on 

 a method of observing the solar prominences in full sunlight ; 

 but Zollner did not obtain a suitable instrument for carrying out 

 his idea till some months later. His " Rever-ionsspektroskop '1 

 which produces two spectra side by side and in opposite direc- 

 tions, has been utilised by himself and others for determining 

 the rate of rotation of the sun by the shifting of the spectral lines 

 at the opposite limbs. Most of his spectroscopic researches 

 relate, however, to the solar prominences. In 1871 Zollner 

 published a paper on the nature of comets in the Leipzig Berichte 

 and the following year he republished this paper together with 

 two papers by Olbers and Bes-el, and a number of chapters " On 

 the Theory of Comprehension " in his well-known book, "Ueber 

 •die Natur der Cometen," which excited much comment at the 

 time, and made him many enemies. About the same time a 

 new chair of " Physikalische Astronomie " was founded at the 

 Leipzig University, to which Zollner (who had for some years 

 been extraordinary professor) was appointed. His a^trophysical 

 activity was at that time at its, height, but soon after he turned 

 his attention to spiritualism, which seems to have absorbed all 

 his energy of late years. 



It is proposed to hold a meeting of the subscribers to the 

 memorial to the late Prof. Rolleston on Thursday, June I, at 

 3 p.m., in the Library of the Royal College of Physicians, for 

 the purpose of determining the form that it shall take. 



Mr. J. L E. Dreyer, assistant at Dunsink Observatory, has 

 been appointed to succeed the late Dr. T. Romney Robinson as 

 director of the Armagh Observatory. 



Prof. Haeckel has returned to Jena from his voyage to 

 Ceylon. 



There have been great rejoicings at Lucerne this week in 

 connection with the opening of the St. Gothard Tunnel. 



With reference to' the communication which we published 

 last week, from Mr. T. F. A. Brown, on the cuckoo singing at 

 night, we have received letters from several correspondents, 

 detailing observations similar to those of Mr. Brown. It was 

 not a previously unknown fact that cuckoos call at night, but 

 the fact is probably not so familiar as it might be. 



M. Janssen took magnificent photographs of the recent eclipse 

 at the Meudon Observatory, Paris, where his revolver was set 

 into operation to determine the first and the last contact. He 

 also took two series of photographs 90 cent, diameter, one nega- 

 tive, and the other positive by direct exposure, with two large 

 refractors. This is the first time that the whole photographic 



power of the Meudon Observatory has been set into operation. 

 In the silting of May 22 of the Academy of Sciences, M. Janssen 

 presented the photographs of the last contact obtained with his 

 revolver during the eclipse, on Daguerreotype plates. He 

 stated that the inspection of the several images proved the con- 

 tact to have taken place at a later time than that calculated. 

 He presented also a large image, 90 cent, in diameter, obtained 

 with his large refractor, and stated that he was [unable to detect 

 any difference in the immediate vicinity of the moon in the 

 representation of facula? and the minute details of the sun's 

 structure. He considered the fact to be opposed to the existence 

 of a sensible lunar atmosphere, as inferred from the spectroscopic 

 observations of the French astronomers in Egypt. 



Ox May 17, M. de Mahy, the French Minister of Agri- 

 culture, presided at the laying of ihe first st me of the Observatory 

 of Vcntcux, at an elevation of 1912 metres above the level of 

 the sea. M. Naguet, deputy to the French Lower House and 

 Professor of Chemistry, delivered an eloquent address on the 

 opportunity of establi-hing mountain observatories, as inaugur- 

 ated by Leverrier on the top of Puy-de-D6me (1465 metres), 

 and practised at the Pic da-Midi (2S771. 



A LOCAL observatory has been established at Besancon, in 

 order to determine the exact time by a-tronomical observations. 

 This city is considered as the headquarters of French watch and 

 clock making. 



Mr. C. L. Wragge, F.M.S., has just established a meteoro- 

 logical and climatological station at the Sanitary Depot, Stafford. 

 Mr. J. B. M'Callum, the borough surveyor, and his brother, 

 Mr. T. M'Callum, have kindly undertaken to observe for Mr. 

 Wragge every morning at nine o'clock (local time). The instru- 

 ments are all standards, verified at Kew. The elements of 

 observation consist of air and earth temperature, moisture, rain- 

 fall, direction and force of wind, kind and amount of cloud, 

 hydrometers, and probabiy ozone. 



Griesbach of Gera (Reuss, Germany) announces the issue of 

 Frisch's edition of Kepler's Works (eight vols. ) at about one-halt 

 the original price. 



The June number of the Americdn Naturalist will contain a 

 biographical notice of the late Mr. Darwin by Dr. Packard, and 

 the articles will be devoted almost exclusively to the subject of 

 Evolution. 



M. W. de Fonvielle writes to us ns follows : — "I am in a 

 position to send a few interesting particulars of an aeronautical 

 ascent which was made on May 18 by M. Eloy, in compliance 

 with the programme alluded to in last week's Nature. The 

 ascent was made on the nth day of a well-defined period during 

 which the prevailing wind was almost without intermission a 

 strong north-easterly breeze which has been detrimental to agri- 

 culture. The sky was clear deep blue, and the air cold and dry. 

 A large number of dense small cumuli, dark, well defined, with 

 ronnd edges, were seen carried by with the wind almost without 

 intermission, except during the eclip=e, when the weather was 

 magnificent. This period having terminated only on the 20 h 

 by a total change of wind, the observations taken may be consi- 

 dered as giving a fair idea of the atmospheric conditions which 

 prevailed during so many days. These clouds were floating at 

 an altitude of more than 2000 metres, and very cold, the ther- 

 mometer having descended abruptly to -4 and -6° centi. 

 grades. When crossing this cloud, the aerial travellers perceived 

 n isolated flake, of snow, but the air seemed illuminated by 

 sudden lights, as if rays travelling from the sun had been reflected 

 by minute icy particles. The balloon having ascended to the upper 

 surface of the clouds, and travelled during more than an hour out 

 of view of the land, the aeronauts were unable to perceive the 



