36 M. Arago o?i Double Stars. 



even analogy for our guide. In truth, the observations of na- 

 turalists could only put in comparison with the solar rays, things 

 terrestrial, and these at temperatures but little elevated. It is 

 then more than probable, concerning this question of the colour 

 of the star, that the great object of observers for a long time 

 to come, must be simply to collect facts. The satisfaction of 

 associating them with the known laws of physics, may probably 

 be reserved for our great-grandchildren. But this is only a rea- 

 son why we should redouble our efforts and our zeal. In the as- 

 tronomical phenomena, the accuracy of observations has often 

 compensated for want of time. And besides, when, after having 

 arrived at the termination of extensive labours, the hope of 

 some important generalization has not been realized, our disap- 

 pointment may find consolation in remembering, that the dis- 

 covery of a single fact^ well observed, well described, and well 

 appreciated, is unquestionably an advance in science ; whilst in- 

 genious and seducing theories which may be received with ge- 

 neral enthusiasm, are often nothing more than a retrograding. 



Fontenelle, Huygens, Gregory, and others, have described, in 

 works which are very well known to the public, the appearance 

 and the movements of all the stars of the firmament, as they 

 present themselves to observers who might be placed on the 

 surface of the Sun — of the Moon — on the planet of Jupiter, 

 followed by his four satellites — of Saturn, surrounded by 

 his prodigious ring, and on Comets, with their eccentric or- 

 bits. Those who delight in these contemplations, have only to 

 transport themselves, in thought, to the planets with which the 

 double stars are unquestionably accompanied, and the united 

 actions of two of these suns with ellipses very eccentric, will 

 then become the occasion of a multitude of interesting researches- 

 The article has already extended itself so far, that we must be con- 

 tented now with simply directing the attention of those explorers 

 of distant worlds, to the binary and ternary groups of coloured 

 stars; to the simultaneous or successive presence of these diffe- 

 rent suns upon the horizons of the neighbouring planets ; to the 

 various combinations of white days, and red, and green days; 

 and to the thousand curious optical phenomena which must 

 be the consequence of all this. There is here something, which, 



