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TABLE OF CONTENTS. 
NO. PAGE 
GENERAL RESULTS OF THE MakERSTOUN OBSERVATIONS— 
System of Observation in different YOALS, tes reese eens eee eeeeeecee eee reeeeeteneenees 9 xi 
Maenetic Decrination— 
Mean Declination and Secular Change,---...+-...sses.sssseeesencnseee sea senenenee 4 xii 
Annual Variations— 
Mean Declination, Beer osebcecuneaccncinanccecseveccecccesees Sataiw aps dain sino Winisisiem cing iscsi 7 xii 
Difference of Daily Means from the Monthly Means, ------+++-++---++++seseeeee 11 xiv 
Diurnal Ranges, --+1----eseeerersr nee nee es ctee eer eee ees see neater sensaeseseeesaseaseners 12 xv 
Ranges of the Monthly Mean Diurnal Variation, --.---+2++--+ssessseeseeeeeeee 13 xvi 
Effect of Disturbance on the Range of the Diurnal Variation, -..--.......... 15 xvi 
Mean Difference of an Observation from the Monthly Mean,--..---+-.-....++5 16 xvii 
Number of Positive Differences, --------+-sssesesecteces eee ccnsenceeseecsesecetenes 17 XViii 
Probable Error of an Observation from the Monthly Mean, «..-..-.......+++- 20 XViii 
Monthly Variations— 
Mean Declination, Sonrswaueronccntsrecsnrecncnscrccesvesevccsceduncectecccenensccescans 91 xix 
Diurnal Ranges, -+++2+:-:+--++eseeeeeeee sec eceeestes ees nen ess seenenesececenanescee ees 29 xix 
Mean Difference of an Observation from the Monthly Mean,...--.+-.--....--. 24 xix 
Diurnal Variations— 
Method of combining Results for Different Years, --+----+++-++-:eeeeeereeseeeee 26 xXx 
Results from all the Observations, for each Month,----+-...-++---ssseereeveeeeee 28 xxi 
Results from all the Observations, for Groups of Months,---...--++.++se+++++- 32 xxii 
Results from Undisturbed Days, for Groups of Months, --.----++--+++:+++--- 36 xxiii 
Effect of Disturbance on the Mean for a Month and for the Year, -----..-. 38 XXiV 
Effect of Disturbance on the Mean for each Hour, ---+-++-+-+++s+eee-sseeeeeneee 39 Xxiv 
Frequency of the Positive and Negative Excursions from the Hourly Mean 
POSItION, «++ seeeceeeeesssecec ee eee sees ene eee tenses see rcn senses sce eneceneseestesnres 40 XXV 
Sums of Disturbances from the Hourly Mean Position,...-----.--++-.++++++++- 42 XXvi 
Mean Excursions of the Magnet from the Monthly Mean Position for each 
Hour, ween cn een su lscence ens ceepccveenccensnaneeserssce senses cencenvesseeresvecocnsunnas 43 XXVli 
Probable Error of an Observation from the Monthly Mean, -.....--.-...-.--» 46 xxviii 
Variations with reference to the Moon’s Hour-Angle,--++---++++1+-ssseseeseees 47 xxix 
