74 MAG X E T I C S U R V B I 1' P E X X S V L V A X I A 



At Toronto (Sec Vol. Ill) the annual decrease of X between L845 and 1852 

 inclusive, wa> 0r0037 (iii absolute measure), or when expressed in parts of X. 

 0.00105. 



Formation of groups for the analytical expression of the distribution of the mag- 

 netic horizontal force, referred to the epoch 1842.0. 



At stations marked with an. asterisk, the horizontal force was determined by 

 vibrations ; at those not so marked, the horizontal force was determined by Lloyd's 

 statical method. 



