3*78 Professor Owen's Address. 



principle, that " electric bodies attract all those that are not so, 

 and repel them as soon as they are become electric by the vicinity 

 of the electric body." The conduction of electric force, and the 

 different behaviour of bodies in contact with the electric, leading 

 to their division, by Desaguliers, into conductors and non-conduc- 

 tors, next followed. The two kinds of electricity, at first by 

 Dufay, their definer, called " vitreous" and " resinous," — after- 

 wards, by Franklin, " positive" and " negative," — formed an im- 

 portant step, which led to a brilliant series of experiments and 

 discoveries, with inventions, such as the Leyden jar, for intensify- 

 ing the electric shock. The discovery of the instantaneous trans- 

 mission of electricity through an extent of not less than 12,000 

 feet, by Bishop Watson, together with that of the electric state of 

 the clouds, and of the power of drawing off such electricity by 

 pointed bodies, as shown by Franklin, was a brilliant beginning of 

 the application of this science to the well-being and needs of 

 mankind. Magnetism has been studied with twoaims; the one, to 

 note the numerical relations of its activity to time and space, both 

 in respect of its direction and intensity ; the other, to penetrate 

 the mystery of the nature of the magnetic force. In reference to 

 the first aim, my estimable predecessor adverted, last year, to the 

 fact, that it was iu the committee-rooms of the British Association 

 that the first step was taken towards that great magnetic organi- 

 zation which has since borne so much fruit. Thereby it has been 

 determined that there are periodical changes of the magnetic 

 elements depending on the hour of the day, the season of the year, 

 and on what seemed strange intervals of about eleven years. 

 Also, that besides these regular changes there were others of a 

 more abrupt and seemingly irregular character — Humboldt's 

 " magnetic storms " — which occur simultaneously at distant parts 

 of the earth's surface. -Major-General Sabine, than whom no in- 

 dividual has done more in this field of research since Halley first 

 attempted " to explain the change in the variation of the magnetic 

 needle," has proved that the magnetic storms observed diurnal, 

 annual, and undecennial periods. But with what phase or pheno- 

 menon of earthly or heavenly bodies, it may be asked, has the 

 magnetic period of eleven years to do ! The coincidence which 

 points to, if it does not give, the answer, is one of the most remark- 

 able, unexpected, and encouraging to patient observers. For 

 thirty years a German astronomer, Schwabe, had set himself the 

 task of daily observing and recording the appearance of the sun's 



