Eclipses 



progress. It was looked upon as a pastime 

 suitable for the idle. It is nevertheless true 

 that the two total eclipses of 1715 and 1724, both 

 visible in France, awakened the deepest curiosity. 

 Both were observed by the King, surrounded 

 by the astronomers of the Academy. In 1724 

 Louis XV. summoned Maraldi and Cassini to 

 the Trianon, and had the thermometer and the 

 barometer brought from his room in order to 

 observe " the variations which might take place 

 during the eclipse, both in the degree of heat 

 and in the weight of the air." It is not difficult 

 to imagine what sort of results could be obtained 

 under such conditions. 



Matters remained practically in this con- 

 dition until 1842. The eclipses of 1748 and 1806 

 were the occasions of fairly accurate descriptions 

 of the phenomena, but it was impossible to link 

 them up with the general laws of Nature, because 

 the science of physics was still unborn. On the 

 occasion of the eclipse of 1842, a man, whose 

 scientific influence was then universally recog- 

 nised Francois Arago published in the 

 Annuaire du Bureau des Longitudes what was 



really an appeal to the scientific world. Arago 



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