PHYSICS AND NATURAL HISTORY OF GENEVA. 197 



the luminous envelope of the sun presents a great number of ppindle-^haped 

 imai^-es, which might be compared to willow leaves strewn confusedly over ita 

 surface. Of these M. Wartmann has presented to the Society a pliotograph 

 taken from the original designs of M. Nasmith. These images seem to be dis- 

 placed one by another, sometimes parallel to thefr axis, sometimes by an angu- 

 lar movement. The preceding obsei'vations have been coufiimed by M. l^it- 

 chard, who announces that they may be repeated with a good telescope of from 

 three to four inches. JI. Wartmann also gave an account of experiments in 

 telegraphic electricity by M. Wheatstone, which he witnessed, and by which 

 it is practicable to obtain despatches written with extraordinary rapidity. 



The same physicist communicated to the Society a note relative to an elec- 

 trical i)henomen(m observed by M. Alizier, teacher at Geneva, July 24, 1856, 

 on the summit of the Oldenhorn. (3f a sudden the staves borne by M. Alizier 

 and the persons who accompanied him began to sound in the manner of the 

 posts of the telegraph. In a few moments a heavy storm of hail descended. 



Professor de la Uive, on his return, in May, 18G'3, from a sojourn in Paris, 

 reported to the Society several new scientific facts v/hich he had gathered. He 

 drew attention, in particular, to an investigation of ^I. Ilelmholtz, hy whiih that 

 savant had arrived, simultaneously with M. W. Thompson, at the conclusion 

 that the earth cannot be liquid in its interior. He also thinks himself entitled 

 to affirm that it is not necessary to recur to the hypothesis of aerolites falling 

 continually into the sun, in order to explain the persistence of the high tem- 

 perature of that body. It sufhccs to admit that the sun, having become heated 

 by an undetermined cause, is now growing cold with extreme slowness; for, 

 according to J\I. Ilelmholtz, the calculations heretofore made greatly exag- 

 gerated the rapidity of refrigeration in regard to that body, because they 

 neglected to take account of an important element, namely, that the sun 

 diminishes in volume as it grows cooler, and that this contraction must de- 

 velop new heat. 



M. dc la Hive presented to the Society, in the name of his son, M. Lucien de 

 la Itive, a memoir on the number of independent equations in the solution of a 

 system of linear currents. <rhis memoir, being wholly mathematical, is not 

 adapted to analysis. 



Professor IMarcet has continued to impart to the Society many facts relative 

 to nocturnal radiation ; among others, to an altogether abnormal refrigeration 

 of the surface of the ground, and of the stratum of air in immediate contact 

 with it, which he has remarked during the first days of March in localities 

 turned tow.ards the north, not only at the hour of sunset, but even during the 

 warmest hours of the day. The author attributes this extraordinary cooling 

 of the surface to the concurrence of several atmospheric circumstances, but 

 more especially to the extreme dryness which had prevailed for some time, and 

 which, as Tyndall has proved, peculiarly facilitates the radiation of terrestrial 

 heat.* 



M. Marcet has taken advantage of the residence of his son in Australia, to 

 induce him to repeat at Queensland, under the 22(\ degree of south latitude, 

 the experiments on nocturnal radiation, which have been recently made in our 

 temperate climates. It would seem to result from these experiments that the 

 ])henomenon of the increase of temperature at certain jicriods of the day, when 

 we ascend some feet above the surface of the earth — a phenomenon so well 

 ;;uthenticatcd in our temperate climates — is not remarked in the ri'gions of the 

 torrid zone either at tlie lising or setting of the sun ; or if it takes ])lace, it is 

 in a degree scarcely sensible, hardly ever exceeding 0^.4 Cent. M. Lucien de 

 la Hive has recently made some observations in Egypt, on the banks of the 

 Nile, which would appear to lead to an analogous result. M. Marcet explains 



* See Arcldves dcs Sciences Physiques et Naturdlcs, April, 1863. 



