562 Intelligence and Miscellaneous Articles. 



to xxvu. preceded by the zero ; and as the rotation of the Sun ap- 

 parently carries a meridian about 13°*19 westwardly per diem, each 

 ordinate may represent any solar meridian within the limits of 

 i3°T9 : thus the zero may represent any meridian between 353°*41 

 and 6°' 59, and xiv. any one between 178 c, 02 and 191 o, 20, and so 

 on. 



I have the pleasure of submitting to the Society the curves of five 

 synodical rotations from observations in August, September, and 

 October 1861, and April and May 1862*. Each presents a well- 

 marked maximum, and the indications of minima are also apparent. 

 The maxima are, without exception, acuminated, showing in each 

 case not so much a diminution of energy as a removal from observa- 

 tion of the active solar surface by rotation. 



The most instructive feature of the curves consists of the portions 

 of the surface of the solar globe indicated as manifesting the greatest 

 energy. 1861, August, the meridians 23° to 208° manifested the 

 greatest energy during the period ; indeed, a much greater activity 

 than the opposite hemisphere. During the' next rotation the energy 

 was greatly subdued ; the curve, nevertheless, exhibited an increase 

 of force between 125° and 297°; and by projecting the September 

 under the August curve, the similarity of features, as regards the 

 increase and diminution of activity, is unmistakeable. 



The October curve, after presenting us with a solar hemisphere 

 perfectly quiescent, meridian 42°, gives us increased action from 108° 

 to 293° ; indeed there had been an increase of activity since 42° was 

 central. Collecting these areas of increased energy, we have a por- 

 tion of the solar surface extending over 274°, manifesting consider- 

 ably more energy than the remaining portion of 86°. The following 

 are the meridians of maxima: — August, 156°; September, 138°; 

 October, 200° ; and this extent of 62°, or thereabouts, may be re- 

 garded as the locality of greatest energy for those months, as referred 

 to heliographic longitudes. The heliographic latitudes of solar energy 

 are well known. 



1862, the April curve exhibits subdued energy from meridians 14° 

 to 173°, then increased energy to 332°, with a maximum at 292°. 

 The May curve manifests during its earlier portion more activity than 

 the April, with a minimum at 156°. This was the meridian of maxi- 

 mum in August ; so that the activity on the hemisphere, of which 156° 

 is the central meridian, is now greatly reduced ; in fact the direction 

 of the curve is reversed. From this meridian the curve manifests 

 increased energy. The two curves for April and May present as 

 perfect an agreement in their features as those of August, September, 

 and October 1861. At the present time the hemisphere of greatest 

 energy is marked by the central meridian 300°, or thereabouts. — 

 Monthly Notices of the Roy. Astronom. Soc. Nov. 14, 1862. 



* The drawings of these curves were exhibited at the Meeting in June 

 last. — Ed. 



