CONTENTS. V 



Page 



Mean Difference of a Single Observation from the Monthly Mean ; Diurnal 



Variation, 387 



Number of Positive Differences ; Annual Variation, 388 



Number of Positive Differences ; Diurnal Variation, 388 



Mean Disturbance ; Annual Variation, • 388 



Mean Disturbance ; Diurnal Variation of the Positive and Negative Sums, 388 



Mean Disturbance; Diurnal Variation of the Positive and Negative Means, 389 



Mean Disturbance ; Diurnal Variation of the Means, 389 



Number of Positive Disturbances ; Annual Variation, 389 



Number of Positive Disturbances ; Diurnal Variation, 389 



Note on the least probable Error of an Observation, 389 



Results for the Magnetic Dip — 



Secular Change, 390 



Annual Period, 390 



Variations with reference to the Moon's Positions, 391 



Diurnal Variation, 392 



Ranges of the Mean Diurnal Variations, 392 



Variation with reference to the Moon's Hour-Angle, 393 



Intermittent Disturbances ; effect on the Yearly Mean, 394 



Intermittent Disturbances ; effect on the Monthly Means, 394 



Intermittent Disturbances; effect on the Hourly Means, 394 



Results for the Total Magnetic Force — 



Secular Change, 395 



Annual Period ; with foot-note on St Helena Observations, 395 



Variations with reference to the Moon's Positions, 396 



Diurnal Variation, 397 



Ranges of the Mean Diurnal Variation, • 397 



Variation with reference to the Moon's Hour- Angle, 398 



Intermittent Disturbances ; effect on the Yearly Mean, 399 



Intermittent Disturbances ; effect on the Monthly Means, •' 399 



Intermittent Disturbances ; effect on the Hourly Means, 399 



Ranges of the three Magnetometers for each Civil Week-Day in 1844, 400 



The Aurora Borealis — 



Annual Variation of Frequency, 401 



Monthly Variation of Frequency, • 402 



Similarity of the laws of Magnetic Disturbance, and of frequency of the Aurora 



Borealis, 402 



Abstracts of the Results for the Meteorological Observations — 

 Results for the Temperature of the Air- — 



Annual Variation of Temperature, 404 



Differences of the Daily Mean Temperatures from the Monthly Means, 405 



Approximations to the Daily Mean Temperatures, 405 



Diurnal Variation of Temperature, • 406 



Approximations to the Monthly Mean Temperatures, 408 



Range of Mean Diurnal Variation, • 409 



Extreme Values and Ranges of Temperature for 1844, 410 



b 



