SCIENCE 



[N. S. Vol. XXXI. No. 800 



SCIENTIFIC BOOKS 



MAGNETIC WORK OF THE BRITISH NATIONAL 

 ANTARCTIC EXPEDITION OF 1901-4 



Thus far three volumes of results in geo- 

 physics have been published by the Eoyal So- 

 ciety of the fruitful Antarctic expedition 

 under the command of Commander E. F. 

 Scott, E.N.: Meteorology (Part I., Observa- 

 tions at Winter Quarters and on Sledge Jour- 

 neys, with discussions by various authors) ; 

 Physical Observations (tidal, gravity, seismic, 

 auroral and ocean magnetic observations), and 

 just recently the volume " Magnetic Observa- 

 tions." We shall confine our attention to the 

 magnetic work and especially to the last vol- 

 ume. 



In the Eeport on the "Physical Observa- 

 tions," Commander L. W. P. Chetwynd, E.N., 

 superintendent of the Compass Department of 

 the British Admiralty, published and dis- 

 cussed the results of the magnetic observations 

 made on board the Discovery during her 

 cruise, as also those obtained on land. From 

 the various sledge journeys, he deduced for the 

 position of the south magnetic pole in 1903, 

 as derived from the magnetic declination re- 

 sults, 72° 50' S. and 156° 20' E.; from the ob- 

 servations for magnetic dip, 72° 52' S., 156° 30' 

 E., hence, average position 72° 51' S., 156° 25' 

 E. While these two positions agree closely, it 

 must be stated that neither depends upon ob- 

 servations made at or in the vicinity of the south 

 magnetic pole, but upon more or less complete 

 observations some distance away. The same 

 is to be said of the position determined by the 

 highly successful Shackleton expedition in the 

 beginning of 1909, viz., 72° 25' S. and 155° 16' 

 E. — forty miles distant of the 1903 position; 

 the observer (Douglas Mawson) had not quite 

 observed a dip of 90°. Were it sufficiently im- 

 portant, much more elaborate observations 

 would be required than any made by the ex- 

 peditions thus far; it is, accordingly, not 

 possible to say whether the difference between 

 the positions for the two expeditions actually 

 represents the secular change between 1903 

 and 1909. 



The Discovery being not strictly a non-mag- 

 netic vessel, the reduction of the magnetic ob- 



servations on board must have presented at 

 times difficulties. Only results for declination 

 and dip are published — no force observations 

 being given, though the instrumental appli- 

 ances admitted also of such work. 



Auroral observations were taken chiefly by 

 the officer of the watch whenever there were 

 displays, the physicist and chief magnetic ob- 

 server, Mr. L. C. Bernacchi, supplementing 

 the observations on special occasions. There 

 are worked out diurnal and monthly periodic 

 variations, change of direction of display dur- 

 ing simultaneous appearances with aurora 

 borealis, sun-spots and magnetic disturbances. 



The volume on " Magnetic Observations " is 

 devoted to a discussion by the superintendent 

 of the Kew Observatory, viz.. Dr. C. Chree, 

 F.E.S., of the magnetic observatory observa- 

 tions made at the Discovery's " Winter Quar- 

 ters," May, 1902, to January, 1904, in Mc- 

 Murdo Sound, latitude 77° 50'.8 S. and longi- 

 tude 166° 44'.8 E. The magnetograph was of 

 the German (Eschenhagen) portable type, the 

 absolute instruments consisting of Kew pat- 

 tern magnetometers and Dover dip circles. 

 An entirely satisfactory site for the observa- 

 tory could not be obtained because of the 

 prevalence of local magnetic disturbances due 

 to the basic volcanic rocks consisting particu- 

 larly of basalt, containing grains of magnetite; 

 observations for standardization purposes were 

 accordingly made out on the ice over the deep 

 sea. 



The arduous duties of observer-in-charge 

 were performed by Mr. Bernacchi, who also 

 assisted Dr. Chree in the reductions and dis- 

 cussions of the data and preparation of the 

 results for publication. There are added at 

 the end of the volume various reproductions of 

 the magnetograms of special interest not only 

 as obtained by the Discovery's observatory, but 

 also at the cooperating stations : Kew, Fal- 

 mouth, Mauritius, Colaba and Christchurch. 



In addition to the usual tables of hou:rly 

 values of the magnetic elements, of the daily, 

 the annual and of the secular variations, and 

 results of related analyses, Chree opportunely 

 devotes considerable space to a discussion of 

 magnetic disturbances of various types. la 



