DIRECTIONS FOR OBSERVING 



THE SCINTILLATION OF THE STARS. 



By CH. DUFOUR, 

 professor at morges, switzerland. 



TRANSLATED yOR THE SMITHSONIAN INSTITUTION, FROM THE " REPERTORIUM FITR METEOROLOGIE, 



ETC.: DORP AT, 1859. 



Even to the most recent times tiie scintillation of the stars has not 

 formed the subject of any series of observations. We find here and 

 there, it is true, some isolated observations, and a few persons have 

 proposed different explanations of this phenomenon, but as yet no 

 course of investigation had been seriously prosecuted. I may claim 

 to be the first who undertook a labor of this kind. My observations 

 at Merges in 1852 were at first but a succession of attempts, but from 

 1853 to the present moment I have allowed no evening, when the 

 stars could be seen, to pass without carefully observing the scintilla- 

 tion. And now, after the dedication of six years to such inquiries, I 

 feel authorized to pronounce that this study is important, and well 

 deserves to occupy a place among meteorological observations. 



But in order that the results may be general and more complete, it 

 is desirable that systematic observations analogous to those which I 

 have undertaken should be prosecuted elsewhere in other climates 

 and under varied meteorological circumstances. There can, at pres- 

 ent, but four stations be counted where I am justified in hoping that 

 this inquiry has been entered upon and will be persistently carried 

 on: 



1. Merges, Switzerland, 46° 30' north latitude, 4° 9' east longitude 

 from Paris. Since 1853 I have taken at this station nearly 24,000 

 observations of scintillation. The principal results thus far obtained 

 from these numerous observations have been published either in the 

 "Comptes Rendus" of the Academy of Belgium, or in those of the 

 Academy of Paris, or in the Notices of the Astronomical Society of 

 London, or in the Bulletins of the Yaudoise Society of the Natural 

 Sciences. I propose soon to communicate some of these observations 

 to the "Repertorium," <fec., as a sequel and complement to the pres- 

 ent directions: 



2. The great St. Bernard, in the Alps, at an altitude of 2,480 

 meters. The monks, who pass the whole year in these elevated re- 

 gions on the borders of perpetual snow, have consented to continue 



