370 



Result.? of Makeestoun Observations, 1844. 



TABLE XXXVI. — Mean Difference of a Single Observation of the Bifilar Magnetometer from the 

 Monthly Mean at the con-esponding hour, for each Hour in each Month of 1844. 



TABLE XXXVII. — Mean Difference of a Single Observation of the Bifilar Magnetometer from the 

 Monthly Mean at the corresiionding hour, for each hour in each of the Astronomical Quarters, 

 and in the Year 1844. 



Diurnal Variation of the Mean Difference. — The mean (lifFercnce is a raaximum twice and a minimum 

 twice in the day, in the variations for the year. The greatest mean occurs at 9'' 10" p.m., but the greatest mean 

 of two consecutive hours is that for 4'' and S*" p.m. : the interpolated epochs are as follow : maxima at 4'' 40" 



