ILLUSTRATIONS. 



Plate 1. Travel and transportation views land magnetic survey expeditions Frontispiece 



Plate 2. Fig. 1. United States Coast and Geodetic Survey theodolite magnetometer of type 1(c) opposite 8 



Fig. 2. Magnetic Survey of India magnetometer of type 2 (6) 8 



Plate 3. Fig. 1. Carnegie Institution of Washington theodolite magnetometer of type 1 (a) 16 



Fig. 2. Carnegie Institution of Washington theodolite magnetometer of type 1 (i) 16 



Plate 4. Fig. 1. Magnetic Survey of France theodolite and magnetometer of type 3 30 



Fig. 2. Land dip circle and compass attachment 30 



Plate 5. Fig. 1. Lloyd-Creak ship dip circle (modified form) 40 



Fig. 2. Wild-Eschenhagen earth inductor 40 



Plate 6. Fig. 1. Induction coefficient apparatus for Weber's method 50 



Fig. 2. Induction coefficient apparatus for Lament's method 50 



Plate 7. Typical field views by observers in British Columbia, Central America, the West Indies, and 



the Bermudas 56 



Fig. 1. View from the station at Chiche, Guatemala 56 



Fig. 2. Mount Ometepec, Nicaragua 56 



Fig. 3. Station near North Rock, Bermuda, at low water 56 



Fig. 4. View of station at Glacier, British Columbia 56 



Fig. 5. View of station at Nelly Island, Bermuda 56 



Fig. 6. Looking south from the station at St. Johns, Antigua, West Indies 56 



Plate 8. Typical field views by observers-in Canada and Greenland 100 



Fig. 1. Station at Marten Creek, Quebec 100 



Fig. 2. Station at Etah, Greenland 100 



Fig. 3. Station at Rupert's House, Quebec 100 



Fig. 4. Station at Sturgeon Tent, Saskatchewan, showing protection of observers against mos- 

 quitoes and sand-flies 100 



Fig. 5 . Portage, northern Quebec 100 



Plate 9. Typical field views by observers in South America, India, and Asia Minor 120 



Fig. 1. Station at Leh, India 120 



Fig. 2. Station at Bogota, Colombia 120 



Fig. 3. View from station at Kizil Langar, India 120 



Fig. 4. Station Amazon 9, Brazil, showing survey launch " El Iman" 120 



Fig. 5. Station at Rumeli Hissar, near Constantinople, showing the Bosphorus 120 



Fig. 6. Magnetic camp at Mamakhatun on the banks of the Tuzla Su, Armenia 120 



Plate 10. Typical field views by observers in Persia, Russia, and China 146 



Fig. 1. Audience at magnetic station Binab, Persia 146 



Fig. 2. Station Tabriz I, Persia 146 



Fig. 3. Station at Gwadur 146 



Fig. 4. Station at Orenburg, Russia 146 



Fig. 5. View southwest to station, Northeast Promontory, China 146 



Fig. 6. Station at Tsinan, China 146 



IV 



