( 193 ) 

 SCIENTIFIC INTELLIGENCE. 



ASTRONOM Y. 



L Comet of' Sftort Period. — M. Humboldt communicated to 

 the Academy of Sciences of Paris the results obtained by M. 

 Encke, relative to the progress of the Comet of Short Period. 

 M. Encke first made the calculations, on the supposition that 

 the comet performed its revolution in vacuo ; and again on the 

 supposition, thai the ether opposed a certain resistance to it. 

 The latter hypothesis has led to a much nearer approximation 

 than the first. In fact, in adopting it, the mean error is only 

 18", while on the supposition that the comet moves in a perfect 

 vacuum, the mean error is 7' 38". These results are therefore 

 of a nature to confirm the hypothesis, which for other reasons 

 is probable enough, of a resistance opposed by the ether to the 

 motions of the heavenly bodies. 



METEOROLOGY. 



2. Malaria. — At a late sitting of the Academy of Medicine in 

 Paris, M. Villernie read a paper on the influence of marshes 

 upon human life, from which he drew the following conclu- 

 sions : — In the salubrious portions of our climates, the winter 

 and spring months are those which give the greatest number of 

 deaths, and the winter is more favourable in the north than in 

 the south. In marshy countries, the greatest number of deaths 

 is in the months of July, August, September and October ; and 

 the evaporation of the marshes is most fatal to persons from one 

 to six years of age. The complaint which generally attacks 

 children, owing to the malaria of marshes, is stated to be an 

 acute gastro-intestinal affection. 



3.. Influence of the Aurora Borealis on the Magnetic 

 Needle. — M. Arago made a communication to the Academy of 

 Sciences on the influence which the aurora borealis exercises on 

 the magnetic needle. We have already had occasion to speak 

 of the discussion raised between M. Arago and several English 

 philosophers, relative to the limits of the extent within which the 

 aurora exercises a perceptible action upon the magnetic needle. 

 M. Arago, from a great number of observations made by him- 



AI'KIL jrjNK 1829- X 



