366 SOCIETY OF PHYSICS AND NATURAL HISTORY OF GENEVA 



at Gotlia, on the parallax of the star of eighth to ninth magnitude, No. 34 of 

 the catalogue of Grooml)ridge, the distance of which from the earth is computed 

 to be but 672,000 radii of our orbit. M. Gautier also directed our attention to 

 the improvements eflPected in different instruments of astronomy and meteorology, 

 and adverted to several new asteroids situated between Mars and Jupiter. The 

 discovery of these planets commenced with the present century, and their num-. 

 ber reaches to-day nearly 100. 



Professor Plantamour gave an account (21st November) of the mechanical 

 processes by help of which he takes observations, registered by a chronograph. 

 The scene of his labors this year was the Righi. These observations have 

 reference to the determination of gravitation, and to other questions submitted to 

 study by the International Conference for the measurement of the meridian 

 between two parallels comprising an arc of 22° in middle Europe. 



Since the admirable discoveries of Kirchoflf and Bunsen relative to the spec- 

 tral anah'sis, the learned have investigated with much ardor the problems bear- 

 ing upon the physical constitution of the sun. One of our colleagues. Colonel 

 E. Gautier, has directed his attention specially to the theory of the spots, and 

 exhibited to us (4th July) an eye-glass manufactured at Munich, which is intended 

 to enfeeble, l»y polarization, the too vivid lustre of the luminary. It would seem 

 to result from observations conducted with this instrument that the solar spots 

 have a very different appearance from that attributed to them. The importance 

 of enabling astronomers to examine these phenomena gave occasion, almost at 

 the same time, to the invention, by the ingenious Leon Foucault, of a silver- 

 plated reflecting telescope. We may hope, therefore, that with the aid of these 

 new instrumentalities science will soon arrive at certain conclusions on this dif- 

 ficult sul)ject. JM. E. Gautier has further given, in our meeting of this da}', 

 (4th June,) the analysis of a memoir published by M. Spoerer, professor at Anclam, 

 on the spots of the sun, in .which the author treats of the law of their velocities 

 of rotation according to their heliographic latitudes, and of the irregularities 

 which disturb that law. In effect, neighboring spots seem sometimes to undergo 

 a sort of torsion, with other anomalous appearances. These anomalies result 

 from the modifications, often very rapid, which are observed in the aspect of the 

 spots, when a magnifying power sutiiciently strong is employed, and atmospheric 

 circumstances are favoraVde. We may then recognize variations, resolutions, 

 and new formations comparable to those of our terrestrial clouds. M. Spa3rer 

 draws from this a confirmation of the idea, already announced by him, that the 

 spots are situated above the brilliant surfaces on which the faciil* are developed. 

 Notwithstanding the accidental changes of velocity whose phases have been 

 studied, the author refuses to believe that the general movement of the solar 

 surface around its axis varies by zones, or by rings parallel to the equator. M. 

 Span-er examines, moreover, the proportional distribution of the spots and faculte 

 on the different portions of the orb, as well as the relations of tliis distribution 

 to the phases of the period of ll years which has been recognized in the fre- 

 quency of these phenomena. He afterwards attacks the Wilsonian theory regard- 

 ing the funnel-shaped spots. He exerts himself to weaken the bearing of the 

 calculations of English astronomers on the mean-proportionals which they have 

 deduced from photographic observations of the sun in relation to that theory. 

 He refutes the attempts of M. Faye tending to introduce a correction termed par- 

 allax of depth, in order to make the calculation of the places of the spots quad- 

 rate with the observations derived from the work of M. Carrington. He main- 

 tains the views of M. Kirchofton the constitution of the sun, and concludes with 

 some ideas touching the manner in which the spots ma}^ be formed. They might 

 be generated by intense ascending currents of gaseous matter which burst forth 

 from the sphere in fusion and become condensed in the solar atmosphere at dif- 

 ferent heights. These foimations would remain or fall back according to the 



