180 



Mr J. D. FORBES on the Horary Oscillations 



.990 ' 



.889 ' 

 .854 ' 



.697 ' 



' .02 = E, 

 = E n 



' + .18 = E IU 

 '+ .41 = E IV 

 ' ..34 = E T 

 ' .13 = E VI 



.446*' + ?' = E V1I 



.407 ' + ' .06 = E TIII 

 .352 ' + ' .05 = E IX 

 .317 *' + ' + . 04 = E X 

 .254 *' + % + .22 = E x , 

 .235 *' + ' + -09 = E XII 



.041 



' .01 = E XII 



From which, proceeding by LEGE:NDRE'S method of minimum 

 squares, we shall deduce of .0106 and ' =. .0254, which, be- 

 ing substituted in the general equation, together with the values 

 of a and found above, it becomes 



z = 3.031 cos * .381 for millimetres, ' 

 = .1193 cos* .0150 for English inches. 



The formula for millimetres being applied to the observa- 

 tions already discussed, we obtain the following, as the nearest 

 possible results : 



By referring to Plate VII., the observed oscillations will be found 

 projected by means of round dots, the distances of which from 

 the line AX representing the quadrant of latitude, indicate the 



