402 Senhor Capello — Kew and Lisbon Magnetic Curves. [May 28, 



23rd of February, which lasted up till 12'* 30™. The horizontal force was 

 in motion from 3*^ 50°^. 



The general appearance of this disturbance at Lisbon is a large decrease 

 of declination and horizontal force, and an increase of vertical force for 

 some hours. 



It is noteworthy that the waves in the Lisbon curves are clean and 

 rounded in the declination and vertical force. The Kew curves show also 

 fewer peaks and hollows than during the former disturbances. 



At Lisbon this general rule is found to exist : the declination disturbance 

 is opposite in direction to the vertical force. The declination curve agrees 

 very well with the Kew curve ; the variations of the latter are larger, as is 

 usual. There is one remarkable circumstance, the first minimum 33™) 

 happens 6*" or 7™ before Kew, the other maxima and minima agree, with 

 the exception of very small differences, which may be attributed to the 

 difficulty of determining precisely the extreme points of the Lisbon curve, 

 on account of their roundness. 



The vertical-force curves show a general similarity, but the connexion 

 between the different phases is not seen. It is remarkable that the general 

 form of the Kew vertical -force curve has a great likeness to the Lisbon 

 horizontal force, but in an inverted order, although the extreme opposite 

 points of maxima and minima do not occur at the same time. 



The horizontal-force curves agree very well up to 8^ ; after this time it 

 is easily seen that the Kew curve agrees almost exactly with the Lisbon 

 vertical force. 



Fourth Disturbance, — Two less important periods follow this period, 

 which terminate about 15^" on the 24th: after ten hours of comparative 

 calm the magnets are again set in motion at Lisbon, by a deviation of the 

 horizontal force and dechnation and a depression in the vertical force, about 

 1*^ 45" on the 25th. This disturbance is composed of three large waves, 

 much agitated, and full ot' peaks and hollows, or serrated. 



At the first glance we see immediately that the general trait of the 

 disturbance is identical at Kew and Lisbon, i. e. the different phases of the 

 three instruments agree with one another. 



The Kew curve generally agrees with the Lisbon one, although several 

 periods are more developed, particularly some waves between 5^ 30"^ and 

 9^ more developed at Kew. The horizontal- force curves also agree ; but 

 it must be remarked that the waves (between 5^ 30"* and 9^), which are 

 most developed at Kew in the declination, are less developed in the hori- 

 zontal force than at Lisbon, 



The two vertical- force curves generally agree ; but the phases at Kew 

 are in advance of those at Lisbon. The small i^eaks (those which can be 

 identified) are inverted and simultaneous. It is also noteworthy that the 

 first vertical-force movement at Kew is opposite to that at Lisbon. 



The vertical-force Lisbon curve is greater in its movements than the 

 declination, and consequently deviates from the general law. 



