Abstkacts foe the Vertical Force. 



147 



TABLE XVII. The Means of the Balance Magnetometer Readings, for periods of Three Months, for the 



Summer and Winter Months, and for the year 1842. 



Periods. 



201-. 



23''. 



2i>. 



5t. 



Mean. 



Range. 



1841. 



Mic. Diy. 



Mie. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



July, Aug., Sept. 

 October, November 

 1842. 



776-9 



787-5 



797-5 



822-3 





45-4 

 61-3 



654-2 



678-2 



699-5 



715-5 











Jan., Feb., March 



958-1 



971-7 



964-9 



980-6 



968-8 



22-5 



April, May, June 



906-0 



905-8 



907-5 



925-5 



911-2 



19-7 



July, Aug., Sept. 



850-0 



849-5 



856-9 



888-7 



861-3 



39-2 



Oct., Nov., Dec. 



797-9 



811-7 



817-4 



826-1 



813-3 



28-2 



Jan., Feb., March, ) 

 Oct., Nov., Dec. / 



878-0 



891-7 



891-1 



903-3 



891-0 



25-3 



April, May, June, ) 

 July, Aug., Sept. j 



878-0 



877-6 



882-2 



907-1 



886-2 



29-1 



The Year. 



878-0 



884-7 



886-7 



905-2 



888-6 



27-2 



In the periods of 1841, the force increases from 20^ till 5^. 



The first quarter of 1842 shews a minimum to occur about 20"^, and before 2^ ; in the second quarter, the 

 minimum seems about 23"^ ; the third, between 20^^ and 23'^ ; and in the last quarter, about 20^ The highest 

 mean is always at 5^. The means for the winter months exhibit a minimum about 2^ ; the means for the summer 

 months have a minimum between 20^ and 23^. 



The means for the year exhibit an increase of force from 20** till 5^, the increase from 23'* till 2^ being very 

 small. 



The mean of the four observations for each quarterly period shews a very regular diminution of vertical force. 

 The ranges are still irregular. 



The following Table has been formed by rejecting disturbances, according to the rule given after Table I. 



TABLE XVIII. — The Monthly Mean Readings of the Balance Magnetometer, for the Hours 20, 23, 2, and 5, 



as Corrected in Table XVII., and rejecting disturbances. 



Month. 



201^. 



23b. 



21'. 



Sh. 



Mean of the 



Four Hours 



.for each 



Month. 



Range of tin 



For each 

 Month. 



Four Hours 



For each 

 two Months. 



1841. 

 July 



August 



September 



October 

 November 



Mic. Div. 



818-8 



Mic. Div. 



817-1 



Mic. Div. 



836-1 



Mic. Div. 



860-6 



Mic. Div. 



Mic. Div. 

 43-5 



18-5 



34-0 



23-8 

 20-7 



Mic. Dir. 

 31-0 

 26-2 



28-9 

 22-2 



16- ? 



808-7 



809-5 



799-1 



817-6 



731-4 



745-4 



737-2 



765-4 



683-1 

 654-4 



691-9 

 657-3 



690-9 

 665-5 



706-9 

 675-1 



693-2 

 663-1 















