210 Mr. H. Wilde. Variation of Magnetic Declination [Mar. 1, 



(Beevor and Horsley). As in the case of the hallux focus, degenera- 

 tion was also confined to the pyramidal tracts of the same side 

 (left) as the lesion, throughout the pons and medulla. At the de- 

 cussation of the pyramids there was also a slight division of the de- 

 generated fibres, but in this case a few fibres only (less than one in 

 ten) went to the lateral column of the same (left) side of the 

 cord. There may have been two or three degenerated fibres left 

 in the direct tract after the decussation, but this could not be 

 positively stated. In the cervical and upper dorsal regions the 

 degenerated fibres gradually decreased in number. At the level of 

 the second dorsal there were a very few degenerated fibres still left 

 in each lateral column. At the third dorsal they had entirely 

 disappeared. 



It seems probable, from these observations, that a second decussa- 

 tion lower down in the cord recrossing does not occur, and that 

 the bi-lateral degeneration observed by Pitres, Sherrington, Langley, 

 Muratoff, and others is a genuine bi-lateral descent of fibres from 

 one hemisphere. 



II. " On the Relations of the Secular Variation of the Magnetic 

 Declination and Inclination at London, Cape of Good 

 Hope, St. Helena and Ascension Island, as exhibited on 

 the Magnetarium." By HENRY WILDE, F.R.S. Received 

 February 19, 1894. 



In a paper which was read before the Royal Society in June, 1890, 

 1 showed that the principal phenomena of terrestrial magnetism and 

 the secular changes in its horizontal and vertical components could 

 be explained on the assumption of an electro-dynamic substance 

 (presumably liquid or gaseous) rotating within the crust of the earth 

 in the plane of the ecliptic, and a little slower than the diurnal 

 rotation. By means of some electro-mechanism, new to experimental 

 science, which I termed a magnetarium, the period of backward 

 rotation of the internal electro-dynamic sphere required for the 

 secular variations of the magnetic elements on different parts of the 

 earth's surface was found to be 960 years, or 22'5 minutes of a degree 

 annually. It was also demonstrated that the inclination of the axes 

 of the electro-dynamic and terrestrial globes to each other of 20 30', 

 was the cause of the inequality of the declination periods about the 

 same meridian in the northern and southern hemispheres; as in- 

 stanced in the short period of outward westerly declination at 

 London, and the long period of outward westerly declination at the 

 Cape of Good Hope and St. Helena. 



The object of the present communication is, firstly, to make a more 





