ASTRONOMY AND METEOROLOGY. SOL 



air. A little more rain falls three kilometres from the woods 

 than at the edge or in the interior. The climate under the trees, 

 therefore, is a sort of sea climate in its thermometric and hygro- 

 metric characters. 



INDIAN SUMMER. 



Prof. J. E. Willet (in the " American Journal of Science," Nov. 

 1867) gives the following facts in regard to the period of several 

 weeks in autumn, characterized by a smoky atmosphere, equable 

 temperature, and cloudless sky, known in America as Indian 

 Summer : 



1. Indian Summer is not confined to North America, but occurs 

 in both hemispheres. 2. The indications are that it is a phenome- 

 non of the temperate zone. 3. The season of its appearance and 

 its period of continuance seem to be slightly different in different 

 countries. 4. There are individual days of smoky weather, dis- 

 tributed through the whole year, and undistinguishable from In- 

 dian Summer in any particular except the time of duration. 



He suggests the following theory on the subject : 



1. The smoldness is produced by real smoke, proceeding from 

 the ordinary fires employed in preparing food, etc., or from extraor- 

 dinary fires in the burning of grass, brushwood, etc. 2. Atmos- 

 pheric currents, subsiding from higher to lower regions, would 

 produce smokiness by depressing the smoke, and, by coming un- 

 der greater pressure, would become relatively dry, and would thus 

 produce relative dryness and equableness of temperature during 

 their continuance. 3. The subsiding of atmospheric currents will 

 be most apparent when a conjunction of circumstances renders 

 them continuous through a series of da3~s, as in the autumn. 4. 

 Descending currents of air are supposed to occur most in the tem- 

 perate zones, to which Indian Summer seems to be peculiar. 



OZONIFEROUS CURRENTS OF THE OCEAN. 



Dr. Moffatt read a paper at the Dundee (1867) meeting of the 

 British Association, embracing the results of observations made 

 between lat. 53 N. and 39 S., and long. 83 E. and 25 W. It 

 was found that as the wind veered with increasing readings of the 

 barometer from south points of the compass through W. to N., 

 ozone disappeared, and continued absent while the wind was in 

 points between N. and E., and that it reappeared as the wind 

 veered with decreasing readings of the barometer to S. points. 

 The disappearance and reappearance of ozone with those condi- 

 tions were so regular, that the changes appeared to be the result 

 of an invariable atmospheric law, and the examination of the law 

 of rotation of the wind led him to believe that the polar current 

 is the non-ozoniferous or that of minimum of ozone, and that the 

 equatorial is the ozoniferous or that of the maximum of ozone. 

 According to the rotation theory, the north polar current forms 

 the north-east " trade," and the south polar the south-east ** trade," 

 while the equatorials form the northern and southern hemispheres 



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