1864.] 



437 



[Chase. 



obtained by the formula ^^ = cos- %^ + sin- 



AY 

 Y ■ 



I have 



taken ^ = — 22°; one scale division of horizontal force r= .000194 ; 

 one division of vertical force = .000792 ; which are almost identical 

 with the values employed by Gen. Sabine in the computation of his 

 Tables of hourly variation in solar and lunar total force. 



In a similar manner I have computed Table VI, showing the 

 average hourly variations, both in solar and lunar total force, in each of 

 the three years which have furnished the data for most of my deduc- 

 tions. The fir-st decimal figures are placed in an upper line, as in 

 Table I. Perhaps the principal utility of this table may be found in 

 some future extension of these investigations, but even now it is 

 interesting, inasmuch as it exhibits the probable influence of periodic 

 causes in shifting the hours of the daily maxima and minima, and 

 as it lends added weight to the preceding tables, by showing that the 

 monthly tide is more regular than the daily tide. 



TABLE V. 



Lunar- Monthly Magnetic Tide of Total Force. 



