DISTURBANCES OF THE TOTAL FORCE. 9 



The ratios of the increasing disturbances of the force have a double progression, 

 as have also those of the decreasing disturbances, though not so well marked. In- 

 creasing disturbances show a principal maximum in January, a principal minimum 

 in June, and a secondary maximum and minimum in August and November, 

 respectively ; decreasing disturbances show a principal maximum in January, a 

 principal minimum in October, and a secondary maximum and minimum in Septem- 

 ber and May, respectively. It appears, therefore, that upon the whole we observe 

 the same laws as at Toronto, viz : the disturbances increasing the force and those 

 decreasing the force follow the same progressive monthly change, and exhibit 

 maximum values about the equinoxes, and minimum values about the solstices. 

 This last remark also applies to the results of the following table in which the 

 annual inequality of the disturbances is given irrespective of sign. 



The minimum of the eleven year period, according to the above ratio, occurred 

 probably in 1845. 



2 December, 1804. 



