266 



MR. VERNON ON THE IRREGULAR OSCILLATIONS 



be added a second maximum which appears to take place 

 in October. 



Some observations, kindly furnished me by Mr. John 

 Curtis, give the following values for the month of August 

 during the last six years : 





Amount of 







Oscillations. 



No 



1855 



0"I46 



16 



1856 



0'126 



18 



1857 



0-095 



II 



1858 



0'102 



15 



1859 



o'ii5 



12 



i860 



0-159 



16 



Means 



0-124 



• ■ 1-47 



The mean daily oscillations, and their number, are then 

 as follows : 





Mean daily Amount. 

 Inches. 







No. 



January 



0-226 



14-9 



February 



0-193 



14-6 



March 



0-191 



14-6 



April 



o-i66 



14-6 



May 



0-135 



i4'i 



June 



0-131 



14-2 



July 



0-121 



15-3 



August 



0-124 



14-7 



September 



0-151 



13-9 



October 



0-193 



15-7 



November 



0-I82 



13-2 



December 



0-206 



15-7 



Mean for the year 



0-168 



14-63 



Total for the year 



61-41 



175*5 



The August values being from six years' observations 

 only, I have not tabulated them in Tables I. and II., as 

 additional years might alter the values to some extent. 



In the diagram, I have added the curve for Dublin from 

 the reductions given by Colonel Sir Henry James in the 

 volume of observations made at the Ordnance Office, 

 Dublin. The features of the two curves are very similar. 

 The Dublin curve, however, does not show so low a mini- 

 mum as the Manchester one; it gives a somewhat higher 

 maximum, and also higher values, in the months of Feb- 

 ruary and October. The two curves being for different 



