23:2 



Royal Society : — 



Table III. {continued.) 



Is 

 Q 











I 



1 



"3 

 .9 



< 





 O 



5 





 t- 



U 



CD 



J3 

 









 -2 S-S 



s|1 







.^0 



~o — 



IS 



i860. 



July 9 



35 



I 





 & 18 



Dr. Bergsma. 



/ 

 68 20*4 



4-o-i 



4-0-8 



68 21-3 



9 



35 



2 





>» 



17*0 



O'l 



o-8 



17-9 



9 



36 



I 





„ 



I4'5 



O'l 



o'S 



i5'4 



9 



23 



36 

 33 



2 



I 





Mr. Chambers. 



13-2 

 i8'6 



O'l 

 0'2 



o-8 



o-8 



14- 1 

 19-6 



23 

 Aug. 16 



33 

 33 



2 





>> 



21-5 

 i6*4 



0'2 

 0- 4 



o-8 

 o-8 



22'5 

 I7'6 



16 



33 



2 





>> 



i6'9 



0- 4 



+o-8 



i8-i 



Sept. 14 



33 



2 





>» 



19-9 



o-6 



o'o 



20'5 



14 



33 



I 





?» 



18-9 



o-6 



O'O 



19-5 



Oct. 19 



33 



2 





,, 



21*2 



0-9 



o'o 



22*1 



J 9 



22 



33 



3° 



I 





Mr. Stewart. 



20*5 

 i8'o 



°'9 

 °'9 



O'O 

 O'O 



21'4 



18-9 



22 



30 



2 





„ 



20*6 



°'9 



O'O 



21-5 



22 



30 



2 





f» 



21*2 



0-9 



O'O 



22*1 



22 



3° 



I 





M 



14*9 



0-9 



O'O 



15-8 



23 



30 



I v 



>> 



iy6 



0-9 



O'O 



i8'5 



29 



3° 



I 





)) 



19*2 



0-9 



O'O 



2CI 



3° 

 Nov. 24 



3° 

 33 



2 





Mr. Chambers. 



23'0 



20'3 



0-9 



l'O 



O'O 



-o'8 



2 3 '9 



2C5 



26 



33 



2, 





,, 



21-3 



I'O 



o-8 



21-5 



Dec. 18 

 19 



33 

 33 



2 





>> 



?> 



I 9 'I 



68 i8'o 



1*2 

 + I'2 



o'2 

 -o'8 



J 9"5 

 68 18-4 



July 1, 



i860, I 



[ean of 71 nhspi 



"vations 









68 19-8 















Collection for Annual Variation. — Wherever, in the middle lati- 

 tudes of the northern hemisphere, observations of the dip have been 

 made with sufficient care, it has been found that, after elimination of 

 the effects of secular change, the north dip is somewhat greater in 

 winter than in summer. In the 3rd volume of the Toronto Observa- 

 tions, pp. cxxii and cxxiii, the following Table is given as the result of 

 fifteen years of careful observation made throughout at the same spot 

 and according to the same method of observation, comprising 1920 

 independent determinations nearly equally distributed in the different 

 months, and averaging about 128 determinations for each of the 

 twelve months ; by combining the months equidistant from July 

 (or the middle of the year), the influence of secular change is elimi- 

 nated : — o / 



Mean of January and the following December .... 75 18*90 N. 

 Mean of February and the following November . . 75 18*98 ,, 



Mean of March and the following October 75 18*63 „ 



Mean of April and the following September 75 18*71 „ 



Mean of May and the following August 75 17*70 ,, 



Mean of June and the following July 75 17*25 „ 



