vi CONTENTS. 
NO. PAGE 
HorizontaL Component or Macnetic Force— 
Horizontal Component in Absolute Measure, «+++1+-.1ssseseeeesssseteeeseees tees 48 XXX 
Secular Change from Observations of Absolute Measure, «++-+-++++++++++-++++ 49 XXX 
Mean Values of the Variations of the Horizontal Component ------+++++---- 51 xxxi 
Comparison of the Secular Change from Observations of Absolute Measure 
with that from Observations of the Bifilar Magnetometer,.----+--------- 53 XXxxii 
Effect of Disturbance on the Mean Value, «-++++++ee-ceeececaseeseeeeereseeeneees 54s xxxii 
Secular change employed in Deducing the Annual Variations,----+++++-++--- 55 XXXii 
Annual Variations — 
Mean Horizontal Component, eenenecaccesecsustuseruuuccccgcctsccsceccesnccnssnsercacs 56 XXXil 
Foot-note on the Annual Period Deduced from the Observations at Toronto 
and Munich, sacle peleucivet es semsetelescvaccntnnobieaitarebciees o¢énecsabscserunsienasine eee XXX 
Effect of Disturbance on the Monthly Means, «++-+.+....+seereessseeeeeeeee serene 57 = - x xxiii 
Mean Horizontal Component from Undisturbed Days, ---+++++++++++++++-+-+++ 58 = xxxiii 
Differences of the Daily Means from the Monthly Means, --- 59 = xxxiv 
Diurnal Ranges, eaniaesia a apedianeieds eaten eeeeeecenen Pane pinto ps pee ppaaier be epiat vane anedenies 60 XXXKV 
Ranges of the Monthly Mean Diurnal Variation, from all the Observations 
and from Selected Days, ous eecpeneccnuacocerevccccssesce+ceevessstenssevecrsenees 61 XXXV 
Mean Difference of an Observation from the Monthly Mean,.--.--+++++.+++++- 63 XXXV 
Probable Error of an Observation of the Horizontal Component, --.----.---- 64 9 xxxvi 
Number of Observations greater than the Monthly Mean,-------++++++--+-.+++ 65 xXxxvi 
Monthly Variations— 
Mean Horizontal Component, Ree Anat TORE Tat oc ENDED OT OR EEO REE SEDER e 66 XXXV1 
Diurnal Ranges, Sonipateins asiapreslis asia ssot Tenisssipeiniesinan arial ccicccce sigh ae sors spsisapiceninye 67 XXxXvii 
Mean Difference of an Observation from the Monthly Mean, 68  xxxvii 
Diurnal Variations— 
Results from all the Observations, for each Month,-----+++++++-++++ seetee enews 69 xxxviii 
Results from all the Observations, for Groups of Monthis,-.-.--«-++++++1+1see+ 70 xxxix 
Results from Undisturbed Observations, for GrORRE¢ of ania seseeeceees } 71 xl 
Effect of Disturbance on the Hourly Means, «++++++++-.sseseereee eee 72 xl 
Frequency of Positive and Negative Departures from the oily _— 
Positions, Raman ele Komee ceaacal desis avlenaia wis, a Cetalaie ate siniaig ciai'b ahia'elncla oxi apieinetetatenss «ie 74 xlii 
Mean Difference of an Observation from the Hourly Mean Position for 
each Hour, vesecssessseseceteeeeceeeeerecseeeeeesensn seer aneeerteeaeeereesseeesenn es 76 xlii 
Probable Error of an Observation from the Monthly Mean,...- 78 xliv 
Variations with reference to the Moon’s Hour-Angle, «++-+.++++++s+:sesreeees 79 xliv 
VERTICAL Component OF MAGnetic Force— 
Vertical Component in Absolute Measure, ----- oor COSCO REDE ERE canassuenece 81 xlv 
Adjustment of Balance Magnetometer in different Years, ------ ste eeeeeeene ees 82 xlv 
Yearly Means of the Variations of the Vertical Component with the Secu- 
lar Change, vadsae cuneate tetlanndees oils mumenteta Cans inter iiisniamalsns\sis-sineecne'e asain ar acd 83 xlvi 
Effect of Disturbance on the Yearly Mean, -++++:++:++eesseseerereeeeeereeeereeseee 85 xlvi 
