632 Influence of the Moon on Atmospherical Phenomena. [Dec. 



she advances towards the Equator. To make this more clear, let us 

 take the average of rain -fall on the days when the moon's declination 

 is great, and compare them with those when it is less, and we shall 

 find the following results. 



In August, 1823. 



The average rain-fall for each day, when the declination of the moon (either 



south or north) was greater than 18° was 0.826 inches. 



When the declination of the moon was between 18° and 9° it was 0.330 

 When the declination of the moon was between 9° and 0° it was 0.174 



In September. 



When the declination of the moon was above 18° it was 0.656 



When between 18° and 9° 0.151 



When between 9° and 0°, 0.297 



An exception to the former observation will be noticed here, since 

 in September, the average, when the moon is between 9° and 0°, ex- 

 ceeds that when she is between 18° and 9°. This I take to be owing 

 to the course of the sun, whose declination is between 9° and 0° in the 

 month of September, and at that time of year, the days when the 

 declination of the moon is within those limits are also the days of 

 conjunction and opposition. As the divisions I have adopted for illus- 

 tration are merely arbitrary, any others may be substituted for them. 

 Thus, if we take the average (for the two months) of the days of 

 maximum declination of the moon, of one day before, and two davs 

 after that, we get an average of 1 . 1 7 inches for each day. In this 

 case, there is an excess, probably owing to the locality of Calcutta, a 

 place which having a great extent of ocean to the south, is more ex- 

 posed to the influx of currents from the ocean, when the moon °-ets 

 to the north of it. But on this I hope to be able to speak farther 

 hereafter. In the period included o in the table there are six days, on 

 each of which the rain-fall was greater than two inches. I here 

 subjoin them, with the corresponding declination of the moon. 



Inches of 

 1823. 



August 2nd, 



Ditto 16th, 



Ditto 17th, 



Ditto 18th, 



September 25th, 



Ditto 26th 



I have also been able to obtain the registers for the last two 

 months of the year 1 824, and for the first three months of the year 

 1825. In this period a few items of rain are registered, which are as 

 follow : 



Rain. 



Decl. of Moon 



2.14 



26° 2' 



N. 



3.32 



26 12 



S. 



2.56 



25 9 



s. 



3.00 



22 59 





2.68 



25 



N. 



4.60 



25 59 





