September 22, 1892] 



NATURE 



489 



nounced maximum which would correspond wiih the sunspot 

 minimum of 1889 (I may mention that the number of thunder 

 days this year is, thus far, small, and the smoothed curve seems 

 likely to go down). The sunspot minimum of 1867 seems not 

 to be represented in the curve. 



Whether or not we may regard this curve as lending support 

 to the view in question, it may at least prove interesting to 

 observe how our summer thunderstorms have varied in number 

 of late years. The Thunderstorm Committee of the Royal 

 Meteorological Society have not yet, I understand, attacked the 

 question of a possible relation to sunspots. May it not be said, 

 however, that the field looks promising ? 



While some other Continental records of thunderstorms 

 treated in the same way yield results similar to those for Berlin 

 and Geneva, there are some which cannot be said to support the 

 view under consideration (though also not positively against it). 

 When one reflects on the unsatisfactory nature of many thunder- 

 storm records extending over a long series of years, vitiated by 

 such things as a change of observers, or of the mode of obser- 

 vation or of record, &c., this need hardly be thought surprising. 



Minimum sunspots and maximum thunder days (smoothed values) indi- 

 cated by an asterisk. 



NO. I I 95, VOL. 46] 



A. B. M. 



The Nova Aurigse. 

 The Nova Aurigse was observed on the night of September 14, 

 with the Newall telescope, under favourable circumstances. It 

 was almost exactly equal in brightness with the star 85" nf ; 

 which of the two was brighter it was difficult to say, because of 

 a peculiarity noted below, but its magnitude may be taken 

 as close upon 10 '3. 



The spectrum, as seen with a compound prism between eye 

 and eye-piece, showed a very faint continuous spectrum, varying 

 fromC toF (or?G); 



a bright line quite, or nearly, coincident with C ; 



three bright lines close together in the green, the least 



refrangible one seeming considerably broader than the 



others ; 

 a faint bright line in the blue (? F) ; 



and with great difficulty I saw at times a still fainter line in 

 the violet. I failed to make out that the bright lines had the 

 dark companions seen in the spring. At first sight the spectrum 

 seemed to consist of a single broad bright line in the green. 



With a power of 215 (without spectroscope) I at first thought 

 that the Nova was diffuse, and resembled a minute planetary 

 nebula rather than a star ; but on focussing more carefully, I 

 made out that the Nova was distinctly stellar ; now, however, 

 the neighbouring stars resembled planetary nebulae. In fact the 

 Nova and neighbouring stars could not be focussed simul- 

 taneously. With a power 500 the effect was of course more 

 marked. The Nova owes its visual magnitude nearly entirely 

 to the light that gives rise to the three green lines in the spec- 

 trum, and it is interesting to note that it was possible to verify 

 a conclusion drawn from this fact and from the nature of the 

 chromatic dispersion of a refractor of 29 feet focal length : — the 

 image of the Nova was distinctly more point-like than that of 

 the neighbouring equally bright star, when each in turn was 

 focussed as carefully as possible. H, F. Newall. 



Ferndene, Gateshead-on-Tyne. 



Atmospheric Depressions and their Analogy with the 

 Movements of Sunspots. 



A SOMEWHAT prolonged absence from home has prevented 

 me seeing until now your note on July 21, page 280, in which the 

 writer remarks that the results of M. Camille Flammarion — 

 published in the July number of IJ Astronomic — "seem to con- 

 firm the view suggested by M. Faye that the constitution of 

 [sun] spots resembles somewhat that of the cyclones with which 

 we are familiar." 



I write to point out that this is not the theory of M. Faye, 

 but, on the contrary, is the theory of Mr. Herbert Spencer, 

 which he published in the Reader for February 25, 1865, and 

 which has since been republished in his collected essays under 

 the title, "The Constitution of the Sun." In it Mr. Spencer 

 first points out the untenability of M, Faye's hypothesis, and 

 then goes on to say : — " The explanation of the solar spots 

 above suggested, which was originally propounded in opposition 

 to that of M. Faye, was eventually adopted by him in place of 

 his own. In the Comples Rendus for 1867, vol. Ixiv., p. 404, 

 he refers to the article in the Reader, partly reproduced above, 

 and speaks of me as having been replied to in a previous note. 

 Again, in the Comptes Rendus for 1872, vol. Ixxv., p. 1664, he 

 recognizes the inadequacy of his hypothesis, saying : — ' 11 est 

 certain que I'objection de M. Spencer, reproduit et developpee 

 par M. Kirchofif, est fondee jusqu'a un certain point ; I'interieur 

 des taches, si ce sont des lacunes dans la photosphere, doit etre 

 froid relativement . . . . II est done impossible qu'ellesprovien- 

 nent d'eruptions ascendantes.' He then proceeds to set forth 

 the hypothesis that the spots are caused by the precipitation of 

 vapour in the interiors of cyclones. But though, as above shown, 

 he refers to the objection made in the foregoing essay to his 

 original hypothesis, and recognizes its cogency, he does not say 

 that the hypothesis which he thereupon substitutes is also to be 

 found in the foregoing essay. Nor does he intimate this in the 

 elaborate paper on the subject read before the French Association 

 for the Advancement of Science, and published in the Revue Scien- 

 tifiqueior March 24, 1883. The result is that the hypothesis is 

 now currently ascribed to him. I should add that, while M. Faye 

 ascribes solar spots to clouds formed within cyclones, we differ 

 concerning the nature of the cloud. I have argued that it is 



