GENEVA SOCIETY OP PHYSICS AND NATURAL HISTORY. 215 



published, and contains the paleontological and geological monograph 

 of the upper strata of the Jurassic formation of the environs of Boulogue- 

 sur-Mer, by MM. de Loriol and Pellat, and the selection of new and 

 but slightly known mosses by M. Duby. The second part of volume 

 xxiv, and also the tirst part of volume xxv, are both in preparation 

 for the press, in the first of which is a memoir by Professor Plautamour 

 on the climate of Greece, and in the second a work by M. H. de Saussure 

 on the Gryllidw. 



ir. — MEMOIRS COMMUNICATED TO THE SOCIETY. 



1. — Astronomy and meteorology — Physical geography. — Professor Plau- 

 tamour gave an account to the society of a memoir which he published, 

 with Professor Hirsch as collaborator, on the determination of the differ- 

 ence of longitude between the Simplon, Milan, and iJ^euchatel. During 

 this work, he ascertained that the Swiss telegraphic lines are not as well 

 insulated as the foreign lines, a circumstance that considerably reduces 

 the velocity of the electric current, owing to the retardation of attraction 

 of the armatures. Allowing for the changes of position that the axis of 

 the instrument undergoes from a unilateral dilatation, caused by the 

 presence of the body of the observer, and the corrections required by 

 personal equations, those of the four observers, MM. Plantamour at the 

 Simplon, Celloria at Milan, and Hirsch and Schmidt at Neuchatel, the 

 following differences were established: 



Between Milan and the Simplon 4' 39".238 



Between the Simplon and Neuchatel 4' 1G".82J: 



Between Milan and Neuchatel S' oG"M2 



The same member also submitted to the society a summary of his 

 observations on the climate of Geneva. He found by examining the 

 mean temperatures for the last fifteen years that they were higher than 

 those of the thirty-five preceding years, so that the mean actually estab- 

 lished for a series of fifty years must be increased by nearly 0o.2. C. (0<^.3 • 

 F.). For every month of the last fifteen years, the mean temperature was 

 higher than the mean temperature deduced from the previous thirty-five 

 years, with the exception of the month of December, in which it was 

 0^.2 O. (0O.3 F.) lower. The greatest increase was 1° 23 C. (2o.2l F.), and 

 occurred in the month of September. The mean temperatures of the 

 whole series of fifty years furnish the following results : January, 

 -00.079 C. (310.85 F.) ; February, -f 10.598 C. (SDo F.) ; March, 

 + 40.597 C. (40O.274F.); April, + 80.967 0. (480.14F.) ; May, -}- 130.197 

 C. (550.75 F.) ; June, + IGO.809 C. (64o 05 F. ; July, + 18O.S07 C. (650.85 

 F.) ; August, + 170.910 C. (G10.24 F.) ; September, + 140.659 C. (58o.3S 

 F.) ; October, + 90.879 C. (490.78 F.) ; I^ovember, -f 40.552 C. (40O.194 

 F.); December, — O0.8O C. (30O.56 F.). 



M. Plantamour, on the other hand, made an examination of his obser- 

 vations by dividing the year into seventy-three series of five days (the 



