IV 



Contents 



OCEAN MAGNETIC OBSERVATIONS— Con. 

 The Magnetic Work of the Carnegie, 1909-1910, 

 BY L. A. Bauer, W. J. Peters, J. P. Ault, and 

 J. A. Fleming. 



General remarks 157 



Description of the Carnegie 160 



Synopses of the Carnegie's cruises, 1909-1916 164 



Cruise I, September 1909 to February 1910. . . 164 



Cruise II, June 1910 to December 1913 IG.i 



Cruise III, .June to October 1914 170 



Cruise IV, March 1915 to September 1916 172 



Methods of work on the Carnegie 176 



Magnetic instruments used in the Carnegie work . 177 

 Marine collimating-compass for magnetic decli- 

 nation 177 



Description 177 



General formulae 17S 



Instrumental constants 1S4 



Method of sea observations 1S9 



Sea deflector for magnetic horizontal intensity 



and declination 190 



Declination observations 190 



Descriptions of the various sea deflectors. . . . 191 



Scheme of horizontal-intensity observations. . 194 



Sea dip-circle for inclination and total intensity . 195 



Marine earth-inductor for inclination 196 



Description 196 



Installation on the Carnegie 200 



Scheme of observation 201 



Mounting of magnetic instruments on the Car- 

 negie 202 



Land magnetic instruments 203 



Instrumental outfit for the Carnegie work 203 



Cruise I, September 1909 to February 1910 203 



Cruise II, June 1910 to December 1913 205 



Cruise III, June to October 1914 208 



Cruise IV, March 1915 to September 1916 210 



General property and supplies 211 



Specimens of observations and of computations. . . 212 



Magnetic observations and computations 212 



Declination observations, August 23, 1913 . . . 212 

 Horizontal-intensity observations, August 23, 



1913 216 



Tot.al-intensity observations, August 23, 1913 218 



Inclination observations, August 23, 1913. . . 221 

 Summary of magnetic observations on August 



23, 1913 225 



Geographic positions at sea 225 



Dead reckoning 226 



Longitude observations (single altitudes) .... 228 



Latitude observations 229 



Latitude and longitude obser^-ations (two-star 



altitudes) 229 



Accviracy of positions at sea 231 



Reduction formulae and determination of constants. 232 



Reductions to standard instruments 232 



Magnetic standards adopted 232 



Constants and corrections for sea instruments . . 232 



Declination observations 232 



Horizontal-intensity observations with sea 



deflector 236 



Inclination obsei'vations 242 



Total-intensity observations 247 



Sea dip-circle corrections 250 



Constants and corrections for land instruments. 252 

 Descriptions of magnetometers, dip circles, 



and earth inductors 252 



Magnetometer corrections 254 



Dip-circle corrections 254 



Earth-inductor corrections 256 



Ocean magnetic observations on the Carnegie, 



1909-1916 257 



Explanatory remarks for final results, 1909-1914. 257 

 Combining weights assigned to different in- 

 struments and methods 259 



OCEAN MAGNETIC OBSERVATIONS— Con. 



Explanatory remarks for preliminary results, 



1915-1916, Cruise IV 259 



Distribution of stations, 1909-1916 260 



Observers and computers 260 



Final results of ocean magnetic observations on the 



Carnegie. 1909-1914 261 



Cruise I, Atlantic Ocean, 1909-1910 261 



Cruise II, Atlantic Ocean. 1910-1911 263 



Cruise II, Indian Ocean, 1911 267 



Cruise II, Pacific Ocean, 1911-1913 272 



Cruise II, Atlantic Ocean, 1913 280 



Cruise III, Atlantic Ocean, 1914 285 



Preliminary results of ocean magnetic observations 



on the Carnegie, 1915-1916 288 



Cruise IV, Atlantic Ocean, 1915 288 



Cruise IV, Pacific Ocean, 1915 288 



Cruise IV, Southern Oceans, 1915-1916 291 



Cruise IV, Pacific Ocean, 1916 294 



Shore magnetic observations for the Carnegie work . 296 



Explanatory remarks 296 



Results of shore magnetic observations, 1909- 



1914 296 



Descriptions of shore stations, 1909-1914 310 



Extracts from Director's instructions for cruises 



and observational work on the Carnegie 316 



Cruise I of the Carnegie, 1909-1910 316 



Cruise II of the Carnegie, 1910-1913 317 



Cruise III of the Carnegie, 1914 323 



Cruise IV of the Carnegie, 1915-1916 323 



Extracts from field reports and abstracts of logs of 



the Carnegie 325 



Extracts from field reports 325 



W. J. Peters and J. P. Ault: Some notes on the 



occurrence of thunder at sea, 1915-1916. . . 325 

 J. P. Ault: On the sub-antarctic voyage of the 

 Carnegie, from Lyttelton to Lyttelton via 

 South Georgia, December 6, 1915, to April 1, 



1916 326 



Abstracts of logs of the Carnegie 330 



W. J. Peters: Abstract of log. Cruise I, 1909- 



1910 330 



Summary of passages for Cruise I of the 



Carnegie 332 



W. J. Peters: Abstract of log, Cruise II, 1910- 



1913 333 



Summary of passages for Cruise II of the 



Carnegie 347 



J. P. Ault: Abstract of log. Cruise III, 1914 . . 348 

 Summary of passages for Cruise III of the 



Carnegie 349 



J. P. Ault: Abstract of log, Cruise IV, 1915- 



1916 350 



Summary of passages for Cruise IV of the 

 Carnegie, as far as San Francisco, Septem- 

 ber 21, 1916 356 



Final summary for Cruises of the Carnegie, 



1909-1916 (September 21) 357 



Auxiliary observations on the Carnegie 357 



Special investigations 357 



Status of general magnetic survey of ocean areas. . 358 



REPORTS ON SPECIAL RESEARCHES. 



Results of Atmospheric-Electric OssERVATroNa 

 Made Aboard the Galilee (1907-1908), and the 

 Carnegie (1909-1916), by L. A. B.vueb and 



W. F. G. SWANN. 



Introduction 361 



Observations on Cruise III of the Galilee, 1907- 



1908 • 364 



Observations on Cruise I of the Carnegie, 1909- 



1910 366 



Observations on Cruise II of the Carnegie, 1910- 



1913 369 



Observations on Cruise III of the Carnegie, 1914. . 372 



