OF THE MAGNETIC FORCE. 



45 



variation for each mouth in the year. In like manner we obtain the diurnal varia- 

 tion of the horizontal force free of the larger disturbances for the summer and 

 winter half, and for the whole year. Table III. will exhibit these differences 

 after their conversion from scale divisions into parts of the horizontal force (one 

 scale division equalling 0.0000365 parts of the horizontal force). The tabular 

 numbers are expressed in units of the sixth place of decimals. A plus sign indi- 

 cates a greater force, a minus sign a less force than the mean value. Casting the 

 eye over the vertical columns, we obtain also a view of the annual inequality of the 

 diurnal variation, which will be examined further on. 



