1864.] 431 [Chase. 



Force, the aggregate is -\- from 3 h. to 5 h., — from 6 b. to2 h. ; and 

 for Nadir Force, the aggregate is + from 23 h. to 10 h., — from lib. 

 to 22 h. ;" p. 644. 



7. Mr. Airy presents some conclusive considerations, "showing 

 that the observed disturbances cannot be produced by the forces of 

 any suddenly created galvanic current or polar magnet," and remarks 

 as follows, respecting his theory : " Its fundamental idea is, that 

 there may be in proximity to the earth something which (to avoid 

 unnecessary words) I shall call a Magnetic Ether; that under cir- 

 cumstances generally, but not always, having reference to the solar 

 hour, and therefore, probably, depending on the sun's radiation or 

 on its suppression, a current from N.N.W. to S.S.E., approximately, 

 or from S.S.E. to N.N.W. (according to the boreal or austral nature 

 of the ether), is formed in this Ether ; that this current is liable to 

 interruptions or perversions of the same kind as those which we are 

 able to observe in currents of air and water; and that their effect is 

 generally similar, producing eddies and whirls, of violence sometimes 

 far exceeding that of the general current from which they are 

 derived;" p. 646. 



8. "And in the relation between E. and W. disturbances and 

 vertical disturbances, there is a point which well deserves attention. 

 When a water-funnel passed nearly over the observer, travelling 

 (suppose) in a N. direction, he would first experience a strong cur- 

 rent to the E., afterwards a strong current to the W (or vice versa), 

 and between these there would be a very strong vertical pressure in 

 one direction, not accompanied by one in the opposite direction ; thus 

 he would have half as many vertical as horizontal impulses. This 

 state of things corresponds to the proportion which we have found 

 throughout for the magnetic disturbances, and to the relation found 

 in Article 18. I may also add that the rule at which we have ar- 

 rived, that the waves of vertical force are few, but that their power, 

 when they do occur, is very great, seems to correspond to what is 

 reported of the whirlwinds of great atmospheric storms ; which, 

 violent and even frequent as they may be, occur very rarely at any 

 assigned place;" p. 647. 



I add a few considerations from Maj. Gen. Sabine's discussions. 

 (Phil. Trans., Vol. 153, Art. XII.) 



9. "The westerly deflections at Kew . . . have a decided double 

 maximum, with an intervening interval of about eight or nine hours. 

 . . . The conical form and single maximum which characterizes the 

 easterly deflections at Kew, belong also to the easterly deflections in 



