CONTENTS 



Special Reports page 

 Construction of Non-Magnetic Experiment Build- 

 ing of the Department of Terrestrial Magnet- 

 ism, by J. A. Fleming 351 



Magnetic Survey of Building 357 



Dip-Needle Errors Arising from Minute Pivot-De- 

 fects, by H. W. Fisk 359 



Conclusions 371 



A Sine Galvanometer for Determining in Absolute 

 Measure the Horizontal Intensity of the 



Earth's Magnetic Field, by S. J. Barnett ... 373 

 Results of Comparisons of Magnetic Standards, 



1915-1921, by J. A. Fleming 395 



Explanatory remarks 395 



No. 1. Agincourt Observatory, near Toronto, 



Canada 397 



No. 2. Cheltenham Observatory, Maryland . . . 403 



No. 3. Christchurch Observatory, New Zealand 408 



No. 4. Dominion Observatory, Ottawa, Canada 414 



No. 5. Eskdalemuir Observatory, Scotland. . . . 422 



No. 6. Greenwich Observatory, England 423 



No. 7. Helwan Observatory, near Cairo, Egypt. 427 



No. 8. Hongkong Observatory, China 429 



No. 9. Honolulu Observatory, Hawaii 431 



No. 10. Kew Observatory, England 435 



No. 11. Loanda Observatory, Angola 441 



Special Reports Concluded page 



No. 12. Lukiapang Observatory, China 442 



No. 13. Pilar Observatory, Argentina 445 



No. 14. Rio de Janeiro Observatory at Vas- 



souras, Brazil 448 



No. 15. Rome Observatory, Italy 451 



No. 16. Samoa Observatory at Apia, Samoa. . . . 451 

 No. 17. Stonyhurst College Observatory, Stony- 

 hurst, England 457 



No. 18. Tananarive Observatory, Madagascar. . 459 

 No. 19. Watheroo Observatory, Western Aus- 

 tralia 461 



No. 20. Washington, D. C. (Department of Ter- 

 restrial Magnetism), and field comparisons. . . 462 

 I. Maintenance of constancy of standards. 462 

 II. Absolute standard in horizontal inten- 

 sity 467 



III. Summary of mean corrections on I. M. S. 470 



No. 21. Various additional observatories 471 



I. Meanook Observatory, 1917 471 



II. Series of comparisons during 1913 by 

 Superintendent Richardson of the 



Eskdalemuir Observatory 471 



III. Series of comparisons during 1898 and 



1902 by Professor Palazzo 473 



General summary and conclusions 474 



