CONTENTS. 



PAGE 



Introduction 1 



Instrumental equipment of parties 2 



Magnetometers 2 



Dip circles 7 



Earth inductors 10 



Accessories 11 



Care of instruments 12 



General methods of work 13 



Selection and description of station 13 



Astronomical work 14 



Theodolite 14 



Chronometer record 14 



Azimuth and time observations 15 



Latitude observations 15 



Magnetic work 16 



Magnetometer observations 16 



Dip circle observations 17 



Earth inductor observations 18 



Diurnal variation and magnetic perturbations. . 18 



Intercomparisons of magnetic instruments 19 



Stations 19 



Method of observations 19 



Field records and computations 20 



Records 20 



Computations 21 



Reports 21 



Reduction formulae and determination of constants. 22 



Astronomical work 22 



Magnetic work 23 



Determination of constants 24 



Specimen summaries of constants 28 



Specimens of observations and of computations. . . 30 



Astronomical observations and computations. . . 31 



Observations of Sun for latitude 31 



Latitude from circummeridian altitudes of the 



Sun 31 



Observations of Sun for azimuth and time ... 32 



Computation of longitude and azimuth 33 



Check azimuth computations 33 



Magnetic observations and computations 34 



Horizontal intensity: oscillations 34 



Horizontal intensity: deflections 35 



Dip observ-ations with dip circle 36 



Declination observations with magnetometer 37 



Summary sheet of results 37 



Total intensity: loaded dip observations.... 38 



Total intensity: deflection observ'ations 39 



Declination observations with compass 40 



Dip obsen-ations with earth inductor 41 



Reductions to standard instruments 42 



Magnetic standards adopted 42 



Preliminary results of comparisons with mag- 

 netic observatory standards 43 



Magnetometer corrections to standard 44 



Dip circle corrections to standard 45 



Earth inductor corrections to standard 50 



Results of land magnetic observations 1905-10. . . 51 



Explanatory remarks 51 



PAGE 

 Results of land magnetic observations 1905-10 Cont. 



Land magnetic observers S3 



Distribution of stations 55 



Special land investigations 57 



Table of Results 58 



Africa 58 



Asia 67 



Australasia 75 



Europe 76 



North America 78 



South America 91 



Islands, Atlantic Ocean 95 



Islands, Pacific Ocean 98 



Professors J. C. Beattie and J. T. Morrison on 

 magnetic work in Southern and Central Africa, 



1908 to 1909 101 



Professor Beattie's account 101 



Professor Morrison's account 104 



Distribution of stations 105 



Extracts from Field Reports 107 



J. A. Fleming, on magnetic work in Central 



America, March to June, 1907 107 



H. W. Fisk, on magnetic work in the Bermuda 



Islands, July and August, 1907 108 



H. W. Fisk, on magnetic work in the West Indies 



and the Guianas, July to December, 1908.. 108 

 J. C. Pearson, on magnetic work in Western 



Canada, August to October, 1907 110 



J. P. Ault, on magnetic work in Northern 



Canada, June to September, 1908 112 



C. C. Stewart, on magnetic work in Western 



Canada, September to November, 1908 113 



C. C. Stewart, on magnetic exploration tiip to 

 James Bay in 1909 113 



C. C. Craft, on magnetic work in British North 

 America and Arctic Regions, July to Sep- 

 tember, 1908 115 



W. H. Siigh, on magnetic work in Cuba and 

 Central America, November, 1908 to July, 1909 1 15 



E. Kidson, on magnetic work in Ecuador and 

 Colombia, July, 1908 to June, 1909 . . 116 



D. C. Sowers, on magnetic exploration trip 

 across China during February to October, 1909 117 



Synopses of additional magnetic surveys, 1905- 

 1910: 



D. C. Sowers, G. Heimbrod, L. A. Bauer, 



E. H. Bowen, P. H. Dike, J. P. Ault, C. K. 

 Edmunds, J. C. Pearson, W. H. Sligh, E. 

 Kidson, and C. C. Stewart 118 



Descriptions of stations 121 



Africa 122 



Asia 128 



Australasia 148 



Europe 148 



North America 150 



South America 172 



Islands, Atlantic Ocean 178 



Islands, Pacific Ocean 183 



