REPORT ON THE TRANSACTIONS 



OF THE 



SOCIETY OF PHYSICS AN D NATURAL HISTORY OF GENEVA, 



FROM JULY, 1863, TO JUNE, 1864. 



BY DR. CHOSSAT, PRESIDENT. 



TRANSLATED FOR THE SMITHSONIAN INSTITUTION. 



In conformity witli article 7 of our laws, I am about to present to tlie society 

 an account of its transactions and its progress during the year in which I have 

 had the honor of being called to preside over it. The society, I regret to say, 

 publishes no special bulletin of its sittings ; the annual report of the president, 

 at the close of his official term, is intended to supply its place. This, however, 

 it can only do imperfectly, because, from the necessarily tardy date of its pub- 

 lication, some of the results communicated must have partially lost the character 

 of finality. However this may be, the greater portion of the labors of the year 

 have been successively inserted either in the present volume of memoirs, or in 

 the archives of the physical and natural sciences of the Bibliothequc Unioerselle ; 

 BO that my task to-day will be limited to a concise recapitulation of those labors. 



Since the end of September last, the society has been deprived of the special 

 collaboration of our excellent colleague, Professor Claparede, whose infirm health 

 has obliged him to withdraw from the functions of secretary of our sittings — 

 functions which for many years he discharged in so distinguished a manner. 

 His place has been filled, provisionally at first, by MM. Alexander Prevost and 

 de Loriol ; and definitively since, by M. Alexander Prevost alone, whom you 

 designated for this office 21st January last. Such has been the obligingness of 

 these gentlemen, and so clear and detailed theii report of the current proceed- 

 ings of the society, that the execution, always more or less difficult, of my 

 present duty has been facilitated to the utmost possible degree ; and I shall be 

 permitted, I am sure, to' present to them, as well in the name of the society as 

 my own, the most sincere acknowledgments. 



Agreeably to the usage adopted in former reports, the present account will be 

 divided into two principal parts : that of the physical and that of the natural 

 sciences ; parts which will be then subdivided into as many special sections as 

 the nature of the communications made to the society may prescribe. In each 

 of these sections we shall speak, first, of the original memoirs which have been 

 read ; and next, say something of the verbal reports which have been made to 

 the society during the year. We commence with astronomy. 



PHYSICAL SCIENCES. 



Astronomy — Memoirs. — M. Emile Gautier read two memoirs on the consti- 

 tution of the sun. With M. KirchhoflF, he regards this body as a globe in fusion, 



