NA TURE 



[June 15, 1905 



to make more widely known the views of a man of 

 science whose speculations were in advance of the age in 

 which he lived. 



In the American Journal of Science (vol. xix. p. 345) 

 Mr. B. J. Harrington describes an investigation of a 

 peculiar variety of foetid calcite found near the township 

 of Chatham, in the Grenville region of Canada. The 

 calcite, although nearly pure, when struck or scratched 

 evolves a powerful and unpleasant odour, which is shown 

 to be due to hydrogen sulphide occluded in the mineral 

 in minute cavities, probably in the liquid state. The 

 proportion of hydrogen sulphide is about 0016 per cent, 

 of the weight of the calcite. A striking property of this 

 variety is that when heated to 160° C. it shows a strong, 

 deep yellow phosphorescence, which persists during several 

 minutes after its removal from the source of heat. 



In part i. of vol. ix. of the Transactions of the Royal 

 Dublin Society, Prof. J. A. McClelland continues the 

 investigation which has already been mentioned in these 

 notes (vol. Ixxi. p. 543) of the relation between the 

 atomic structure of substances and their power of giving 

 rise to a secondary radiation under the influence of the 

 j3 and 7 rays of radium. It is shown that as the atomic 

 weight increases the secondary radiation also increases, 

 and that, as regards the latter, the elements may be 

 arranged in a series of groups which correspond strictly 

 with the periods of Mendel^eff's classification. The curve 

 connecting atomic weight and the power of giving rise 

 to a secondary radiation is of particular interest, as it 

 throws light on the manner in which atoms are built up 

 from electrons. It is important to note that the density 

 of a substance has comparatively little influence on its 

 power of producing secondary radiation. 



The catalogue of geological literature added to the Geo- 

 logical Society's library during the year ended on 

 December 31, 1904, has just been issued. The catalogue 

 is published by the Geological Society at the price of 2s. 



The index number of the Psychological Reviciv for 1904 

 has just been published by the Macmillan Company of 

 New York. The index is a very complete bibliography 

 of the literature of psychology and cognate subjects for 

 the year 1904, and has been compiled by Prof. Howard 

 C. Warren, of Princeton University. It occupies no less 

 than 240 pages, and contains 3445 entries of separate papers 

 or volumes by psychologists of all nations. 



OUR ASTRONOMICAL COLUMN. 



A Probable Nova in OniiucHus. — From an examin- 

 ation of the Henry Draper memorial photographs in 

 1899, Mr. Fleming came to the conclusion that the star 

 R.S. Ophiuchi was of the Nova type. Its spectrum, as 

 shown on a plate taken on July 15, 1898, contained the 

 hydrogen lines H^, He, H5, H7, and H|8, and the lines 

 at k\ 4656 and 4691 as bright lines, thus resembling 

 Novai Sagittarii and Geminorum. A spectrum obtained 

 on July 14, the preceding day, confirmed the presence of 

 these bright lines, whereas one photographed on .'\ugust 

 28, 1894, was simply of the K type without bright lines. 



Miss Cannon recently examined the light curve of 

 this star since 1888, and found that it varied consider- 

 ably and rapidly about the time at which the bright 

 line spectra were obtained. Thus on May 31, 1898, the 

 magnitude was only 108, but a month later, on June 30, 

 it had become 77, and it subsequently decreased, at the 

 regular rate of about one magnitude per month, until on 

 October 8 itwas only 108 again. A minor recrudescence 

 took place in 1900, followed by another decrease, and 



since then the magnitude has remained faint at about 10 o, 

 just as other Novce, e.g. P Cygni, have, since the waning 

 of their initial outbursts, remained fairly constant. An 

 examination of several good chart plates revealed only a 

 single star in the position occupied by this body. As 

 many previous Novek, having spectra similar to that of 

 this star at its brightest, have been shown to have existed 

 in the same positions prior to their discovery, Prof. Picker- 

 ing contends that R.S. Ophiuchi should be classed as a 

 Nova, when its proper designation would become Nova 

 Ophiuchi No. 3, the new stars of 1604 and 1848 having 

 appeared in the same constellation (Harvard College 

 Observatory Circular, No. 99). 



Observations of Prominences on the Sun's Limb. — 

 In No. 5, vol. xxxiv., of the Memorie della Societd degli 

 Spettroscopisti Italiani, Prof. Mascari gives, for 1904, his 

 usual annual summary of the observations of solar 

 prominences made at the Catania Observatory. From the 

 tables given we see that the prominence activity was 

 augmented during 1904, also that the law that as the 

 daily frequency of prominences increases their mean helio- 

 graphic latitude decreases was confirmed ; in 1902 the 

 value was 48°-4, in 1903 it was 42°- 1, but in 1904 it i 

 decreased to 35°6. During the first quarter of last year I 

 the prominences occurred with a greater frequency in the 

 southern hemisphere, but during the other three quarters 

 the reverse was the case, the mean daily frequencies for 

 the year being : — northern hemisphere 1-57, southern 

 hemisphere 133. 1 



A plate issued with the preceding number of the same ' 

 journal shows, graphically, the positions and magnitudes 

 of the prominences observed on the limb during the period 

 March 14 to May 11, 1902, at the observatories of 

 Catania, Kalocsa, Odessa, Rome, and Zurich. By thus 

 combining the observations made at different places, it 

 was possible to obtain a complete daily record for 

 the whole period, with the exception of four days. Several 

 outstanding disturbances are obvious, especially one 

 extending from N. 42° W. to N. 84° W., and enduring as 

 a limb disturbance from March 14 to 18. 



Determination of Meteor Radiants. — Commenting on 

 a mathematical paper, on the determination of meteor 

 radiants, recently read before the Royal Astronomical 

 Society by Mr. Chapman, Mr. Denning issues a warning 

 against the acceptance of any radiant, except in special 

 circumstances, determined from the observations of less 

 than five paths. The errors of observation, unless the 

 observer has had much experience, are sufficient to over- 

 burden the catalogue of radiant points with a number 

 of false radiants if three paths be accepted as suflficient 

 data. When the altitude of the radiant is small, the 

 meteors traverse long paths, and a consideration of three 

 of these may give a satisfactory value, otherwise three is 

 wholly insufficient. Mr. Denning advises meteor observers 

 to keep a careful record of all faint showers suspected, 

 and endeavour to corroborate them at the subsequent re- 

 currences of the same epochs. By doing this and com- 

 bining the results, well supported radiants mav be 

 established (Monthly Notices of the Royal Astronomical 

 Society, April). 



T 



THE DEVELOPMENT OF SPECTRO- 

 CHEMISTRY.' 



HE series of optical researches carried on by the late 

 Dr. J. H. Gladstone, at first in collaboration with 

 the Rev. T. Pelham Dale, established the important fact 

 that Newton's expression for refraction, (ir— i)/d, is not 

 constant, but varies considerably with the temperature. On 

 the other hand, it was found that the more simple ratio 

 (n—i)fd remains practically constant. 



Soon after i860, Hans Landolt came forward with his 

 optical researches. He began by confirming the results of 

 Gladstone and Dale. He proceeded a step further, how- 

 ever, by following the example of Berthelot, and com- 

 paring the refractivity, not of equal, but of molecular 



1 Abridged from a discourse delivered at the Royal Institution on 

 Friday, May 26, by Prof. J. W. Briihl. 



NO. 1859, VOL. 72] 



