154 Mr. J. N. Lockyer. Preliminary Report to the [Dec. 15, 



from the outside is the same as that produced by such a current 

 approaching it from the inside. 



Various other phenomena, such as temporary reversals of the direc- 

 tion of rotation, successive action of the coil and iron tube, &c, &c, 

 are recorded in the paper. 



With a Selenoicl. — An axial current flowing upwards from a south to 

 a north seeking pole, produces dextro rotation at the former and laevo 

 rotation at the latter. 



With, a Tubular Magnet. — These two directions are reversed at all 

 distances between the two neutral points near the poles of the magnets, 

 but not beyond. The phenomena, therefore, of rotation are more 

 complex with a tubular magnet than with a selenoid. The directions 

 of rotation produced by a vertical current outside a vertical coil or 

 magnet are the same as those produced by it inside a coil alone. 



The reversals of direction of rotation near the poles, which occur 

 when a tubular magnet is employed, appear to be due to the inner 

 surface of the magnet, and to the position of that surface in relation 

 to the vertical current in the liquid. The direction of rotation and 

 the points of reversal appear to be all independent of each other. 



The action of radial currents is more simple than that of axial ones, 

 especially near the poles of a magnet. With radial currents, either in 

 the liquid or electrodes, there is no reversal, either at the centre of the 

 magnet or coil, or at the poles or beyond them, or near the outside of 

 the coil or magnet. 



The experiments show the entire group of rotations produced inside 

 and outside a vertical coil (with and without an iron core), and near 

 its poles, by radial currents ; also the group of rotations produced by 

 vertical currents inside and outside a vertical coil and near its poles, 

 and also those produced inside and outside and near the poles of a 

 vertical coil with a tubular iron core, by such currents. 



The experiments show in a conspicuous manner the difference of 

 property of the interior surface of a hollow magnet and of that of a 

 voltaic selenoid having the same kind of poles at their corresponding 

 ends. This difference of property is well known, but is illustrated in 

 the paper in a new way experimentally. 



III. " Preliminary Report to the Solar Physics Committee on the 

 Sun-spot Observations made at Kensington." By J. N. 

 Lockyer. Communicated to the Royal Society at the re- 

 quest of the Solar Physics Committee. Received Novem- 

 ber 29, 1881. 



Since the commencement of the observations, in November, 1879, of 

 the twelve most widened lines in sun-spots, about 220 observations have 



