310 Transactions of the South African Philosophical Society. 



declination at Falmouth and Kew. Schmidt's results (Archiv. des 

 Erdmagnetismus Heft I.) show that there are two maxima and minima 

 in the values of AD for a period corresponding to that with which we 

 are dealing at Toronto, Hobarton, and St. Helena. In this respect 

 the Cape is no exception, as similar maxima and minima are readily 

 observed in the case of the Declination results. The figures for the 

 Horizontal Intensity, obtained from the same sources, also show 

 agreement. 



Consider the value of the ratio - for each month, where b is the 



a 



arithmetic mean of the quantities A" for the month, and a is the 

 arithmetic mean of A' for the same month. For purposes of com- 

 parison I have calculated from Schmidt (Archiv. des Erd. Heft I.) 

 the value of the ratio for Declination and Horizontal Intensity for 

 stations, Hobarton, Toronto, and St. Helena, and have collected 

 corresponding results from Chree (Phil. Trans. [A] , vol. 203). The 



I 



II 



III. . 



IV. . 



V 



VI. . 

 VII.. 

 VIII. 

 IX. . 



X 



XI. . 

 XII.. 



Cape. 



d 

 o 



,Q 



O 



Toronto. 



St. Helena. 



Katharinen- 

 burg. 



Pawlowsh. 



Batavia. 



D. 



1-89 

 1-29 



•79 

 1-98 



•84 



•9 

 2-24 

 1-63 

 2-29 

 1-26 



•88 



•79 



H. 



2-78 

 1-70 

 1-85 

 1-09 

 1-16 

 1-82 

 2-77 

 5-17 

 1-72 

 1-09 

 •95 

 1-0 



D. 



•43 

 •58 

 •52 

 •85 

 •86 

 •77 

 •85 

 •60 

 •48 

 •45 

 •41 

 •46 



H. 



•6 



•8 



•6 



1-4 



1-5 



1-1 



1-3 



1-0 



•7 



•5 



•8 



1-9 



D. 



•69 



1-18 

 •59 

 •22 

 •38 

 •23 

 •51 

 •37 

 •24 

 •54 

 •64 

 •73 



H. 



•6 

 2-0 

 1-2 

 1-2 

 1-6 



•9 

 1-8 



•6 



•5 

 1-1 



•9 

 1-7 



D. 



1-47 



1-28 

 •59 

 •60 



1-19 

 •61 



2-09 

 •29 



1-21 

 •65 

 •47 



1-31 



H. 



•9 

 •9 

 •7 



1-1 

 •5 

 •5 



3-0 

 •4 

 •4 

 •8 



1-1 

 •3 



D. 



•20 

 •95 

 1-10 

 •53 

 •53 

 •60 

 •48 

 •34 

 •54 

 •71 

 •88 

 •42 



H. 



1-30 



1-17 



1-12 



1-26 



•58 



•95 



1-13 



•72 



•85 



1-47 



2-39 



•50 



D. 



H. 



D. 



H. 



•78 

 •85 



1-06 

 •55 

 •77 

 •82 

 •80 

 •74 

 •73 

 •84 



1-01 

 •70 



1-30 



2-09 



1-20 



•51 



•68 



•48 



•54 



•40 



•50 



•62 



1-07 



1-09 



1-04 



1-65 



1-62 



•83 



•97 



•67 



•80 



•40 



•58 



•97 



2-10 



3-08 



•60 

 •45 

 •78 

 •55 



•71 

 •46 



•74 

 •57 

 •77 

 •41 

 •40 

 •52 



D. H 



•63 

 •25 



•23 

 •55 



•86 

 •35 

 •80 

 •69 

 •26 

 •23 

 •52 

 •18 



•26 

 •55 

 •67 

 •35 

 •55 

 •78 

 •56 

 •75 

 •69 

 •70 

 •29 

 •76 



latter, however, do not lend themselves so well to purposes of com- 

 parison with Cape results, as they refer to a period which does not 

 correspond to that with which we are dealing. In the case of 

 Declination at the Cape and St. Helena agreement is very con- 

 spicuous. For nearly the whole mean year - increases or decreases 



together at the two stations. 



The seasonal values of the ratio show excellent agreement for the 

 stations under consideration. We see from the figures that the 

 maximum value occurs in winter. In the case of the Declination 



