148 



Absteacts for the Vertical Force. 



TABLE XVIII. — continued. 













Mean of the 



Range of the Four Hours | 



Month. 



201-. 



sai-. 



Sh. 



5^. 



Pour Hours 

 of each 

 Month. 



For each 

 Month. 



For each 

 Two Months. 



1842. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 



Mic. Div. 

 11-? 



January 



987-2 



995-3 



992-4 



998-3 



993-3 



11-1 



9-6 



February 



9731 



981-2 



977-6 



979-9 



977-9 



8-1 



11-5 



March 



928-2 



937-7 



928-1 



943-0 



934-2 



14-9 



18-2 



April 



924-2 



920-9 



915-4 



936-9 



924-3 



21-5 



32-9 



May 



918-1 



904-0 



899-6 



944-0 



916-4 



44-4 



29-4 



June 



895-9 



8930 



886-1 



900-6 



893-9 



14-5 



32-9 



July 



884-9 



849-2 



841-2 



892-5 



866-9 



51-3 



32-6 



August 



860-9 



8540 



847-0 



860-0 



855-5 



13-9 



21-4 



September 



839-8 



847-9 



855-9 



868-8 



853-1 



29-0 



27-3 



October 



817-4 



827-3 



825-2 



843-1 



828-2 



25-7 



24-7 



November 



801-9 



814-4 



821-5 



826-1 



816-0 



24-2 



18-4 



December 



782-4 



788-7 



7930 



795-1 



789-8 



12-7 





The rejection of disturbances produces a considerable difference in the results deduced from Tables XVI. and 

 XVII. 



In 1841, the highest means occur at 5^ ; the lowest mean in July is at 23'', in August at 2\ and in Sep- 

 tember, October, and November, at 20''. 



A maximum occurs in August, September, and October, about 23''. 



A minimum occurs in July, between 20'' and 23'', in August, September, and October, about 2^. 



In 1842, the highest means, with two exceptions, are at 5'' ; in February, the highest is at 23'', and in August, 

 at 20'' ; but they differ little from the mean at 5''. 



The lowest means in the first three and last four months of the year are at 20''. In the remaining months 

 at 2*'. In March, the means at 20'' and 2'' are equal. 



A maximum occurs in January, February, and March, about 23'', in October about 22''. 



A minimum occurs in January about 2'', in February between 2'' and 5'', in March, April, May, June, July, 

 August, and October, between 23'' and 2''. 



The mean of the four hours for each month shews a decrease of vertical force from the beginning to the end 

 of the year ; the diminution from month to month is rather irregular. 



The ranges for each month are irregular ; but when the mean of each two months is taken, the increase of 

 tange from summer to winter is very regular, and well marked. 



The following Table is formed from Table XVIII. 



i 



