20 REPORT — 1865. 



quired in every large town, especially in Birmingham itself, the population of which 

 is increasing at the rate of about 5000 yearly, a distinct record of the new cases of 

 disease, the nature of the localities in which they have occurred, and the condi- 

 tions of atmosphere under which they have been formed. The principal local results 

 obtained are — Mean atmospheric pressure (reduced to sea-level), 29'958 inches ; 

 mean temperature, 47°'0 ; the highest temperature, 89 J, 2 ; the lowest mean, — 2° - 5; 

 mean yearly rainfall, 27'991 inches ; greatest fall, 35T6 ; least, 21-21 ; mean num- 

 ber of days on which rain fell, 176. 



Description of the Magnetic Storm of the Beginning of August 1865, as re- 

 corded by the Self-recording Magnetographs at the Kew and Lisbon Obser- 

 vatories. Bg J. B. Capello and B. Stewart, F.R.S. 



The great magnetic storm which broke out about the beginning of August last 

 will be remembered as occurring at the time when anxiety began to be felt respect- 

 ing the fate of the Atlantic cable. The following are the general characteristics 

 of that storm, and apply both to Kew and Lisbon, since these two places were 

 similarly affected by the storm. It first commenced about 5.40 p.m. (G. M. T.) of 

 the 2nd of August ; but it broke out with great violence, and with those rapid 

 motions which form the mark of a large disturbance, about 5 a.m. of the 3rd of 

 August, and this outbreak lasted until midnight of that day or early morning of 

 the 4th of August. The disturbance then ceased for about twenty-four hours, re- 

 commencing a little before midnight of the 4th of August, and lasting till about 



4 p.m. of the next day. There remained, however, traces of the disturbance for a 

 considerable time after this date. There were thus two great outbreaks forming 

 this storm, the first commencing on the 2nd of August at 5.40 p.m., or more notably 

 on the 3rd of August, at 5 a.m., and lasting till early morning of the 4th of August, 

 the second commencing about 11 p.m. of the 4th of August and lasting till 4 p.m. 

 of the 5th of August. With regard to the first of these two outbreaks, from about 



5 a.m. until 11 a.m. on the 3rd of August the horizontal and vertical components of 

 the magnetic force were both considerably decreased by it, while in the afternoon of 

 the same day they were both, but especially the vertical-force component, consi- 

 derably increased. The westerly declination, on the other hand, was, on an average, 

 increased during the greater part of this outbreak, although towards the end it was 

 probably diminished. Broadly viewed, this disturbance may be said to have 

 begun with a tendency to diminish both components of the force and to increase 

 the westerly declination, and to have ended with a tendency to increase both com- 

 ponents, but especially the vertical force. On the whole, the effect of the dis- 

 turbance was, probably, to diminish both components of the force, and to increase 

 the declination. With regard to the second of the two outbreaks which together 

 constituted this storm, it began by diminishing both components of the force, if 

 we except a comparatively small increase of horizontal force at the very com- 

 mencement, and ended by slightly increasing both components at Kew. With 

 respect to the westerly declination, this element was at first somewhat diminished, 

 but it was ultimately increased by this disturbance. Broadly viewed, the charac- 

 teristics of this second outbreak were similar to those of the first, exhibiting a 

 tendency to diminish both components of force, and slightly to increase the decli- 

 nation. In comparing the storm with the greater one of August-September 1859, 

 as registered at Kew, we find the following points of resemblance : — 1. Both 

 storms consisted of two separate outbreaks, and both the outbreaks of both the 

 storms began during the hours of night or early morning. Thus we have — 



Storm of Aug.-Scpt. 1859. 



1st Outbreak 28 Aug. 10|p.m. 



2nd do 2 Sept. 5 a.m. 



Storm of August 18G5. 



1st Outbreak 3 Aug. 5 a.m. 



2nd do. 4 Aug. 11 p.m. 



— 2. Both outbreaks of both storms tended at first to diminish both components 

 of the force, and to increase the westerly declination, but changed in the afternoon 

 of next day into forces tending rather to increase both components. This is a 

 very good instance of the influence (proved to exist by Gen. Sabine) of the hour 

 of the day upon the character of the disturbance. Thus we see that in all these 

 cases we have, in the early morning hours, a diminution of both components of the 



