PART I. ON MAGNETIC STORMS. CHAP. III. jg! 



At Honolulu the conditions are very quiet, with the exception of the period about I4 h 45. If we 

 look at the //-curve about the time mentioned, we shall find some similarity between its course here and 

 at Christchurch, a similarity which may lead to the bringing of the perturbations here and at Christchurch 

 into connection with one another. 



The field during this second section is given on three charts (IV, V and VI). 

 Chart IV represents the conditions at I4 h 45, 



V at three hours, viz. i6 h io m , i7 h , and 17^ 30"*, and 



VI at i8 h o m . 



As we see from the curves, the perturbations within this period cannot be regarded as consisting 

 mainly of a single perturbation, but as a series of short, principally polar impulses with somewhat chang- 

 ing centre. 



Axeleen occupies a peculiar position, the perturbing force there remaining throughout fairly constant 

 both in magnitude and direction. The conditions here do not in any way resemble those at the other 

 Norwegian stations, the force at Axeleen being almost equally strong, but opposite in direction, and the 

 current-arrow principally directed towards the west. The conditions at Axeleen, moreover, show an 

 entirely independent course, in which there is nothing answering to the successive maxima and minima 

 that we notice, for instance, at Kaafjord. 



On Chart IV, for 14'* 45, we find at the three southernmost Norwegian stations, current-arrows 

 of considerable strength directed eastwards along the auroral zone. In Europe and the west of Asia, 

 there is now a corresponding area of divergence. At Sitka there is a fairly strong current-arrow directed 

 towards the north-west; and at the same time, the other American stations indicate that there is an 

 area of convergence. It would appear from the form of this area that we had before us the effect 

 of polar precipitation with the storm-centre a little to the west of Sitka, that is to say in a district situ- 

 ated on the night-side. The direction of the current-arrows round this district must then be westerly. 

 The field as it appears on this chart thus seems to be somewhat complicated, but the form is not 

 an unknown one. If we compare these conditions with those, for instance, shown on Charts IV and V 

 for i6 h 45 m and 17'' on the gth December, 1902 (p. 75), we find that the resemblance is striking. 

 The time, moreover, should be noted at which these two storms commence. The conditions remain 

 more or less constant throughout this period, the changes consisting principally only in a certain amount 

 of variation in the strength of the forces, but little in their direction, so that the form of the field is not 

 essentially changed, at any rate in higher latitudes. The changes that do occur can all be accounted 

 for by the translocation of the systems. The period extends, as we have said, from I4 h to i8 h and we 

 thus here too find a resemblance to the gth December. 



In the preceding perturbation on the I5th February, we also found exactly analogous conditions at 

 these stations during the first two sections. There does not seem to be any essential difference between 

 the fields on these two days, the only ones being that on the present occasion the stormcentre, with its 

 eastward-pointing arrows at the more southerly Norwegian stations, stands out more distinctly, and that 

 the system extends farther east than in the preceding storm. The current-arrows are also stronger, and 

 the area of divergence is more distinct. 



The resemblance between the fields is so great that it is impossible to regard it as chance; and 

 we involuntarily receive the impression that the field before us is possibly typical of the polar storms 

 that appear at this time of day, just as we have previously found the typical form of the field that forms 

 about midnight, Greenwich time. In what way, in my opinion, the field is to be understood has been 

 already indicated in the description of the preceding storm, and I will therefore only refer the reader to it. 



