424 Prof. 0. Lodge on the Discharge of a Leyden Jar. [March 8, 



tlirougli the tube upon our rotating mirror, and to look now, not at 

 tlie spark, or not only at the spark, bnt at the fiiint band into which 

 the last residue of light coming through polariscr and tube and 

 analyser is drawn out. (Analyse the light in rotating mirror.) 



At every discharge this faint streak brightens in places into a 

 beaded band : these are the oscillations of the polarised light : and 

 when examined side by side they are as absolutely synchronous with 

 the oscillations of the spark itself as can be perceived. 



Rotating the analysing Nicol a little, one sees every alternate bead 

 grow fainter, while the other alternate ones brighten ; thus directly 

 establishing the fact of alternations, as distinct from intermittences. 

 A certain definite rotation will obliterate one set altogether, and make 

 the beading appear twice as coarse, as if it belonged to the octave 

 below. [For further details see * Philosophical Magazine ' for April, 

 1889.] 



Out of a multitude of phenomena connected with the Leyden jar 

 discharge I have selected a few only to present to you here this 

 evening. Many more might have been shown, and great numbers 

 more are not at present adapted for presentation to an audience, being 

 only visible with difficulty and close to. 



An old and trite subject is seen to have in the light of theory an 

 unexpected charm and brilliancy. So it is with a great number of 

 other old familiar facts at the present time. 



The present is an epoch of astounding activity in physical science. 

 Progress is a thing of months and weeks, almost of days. The long 

 line of isolated ripples of past discovery seem blending into a mighty 

 wave, on the crest of which one begins to discern some oncoming 

 magnificent generalisation. The suspense is becoming feverish, at 

 times almost painful. One feels like a boy who has been long 

 strumming on the silent key-board of a deserted organ, into the 

 chest of which an unseen power begins to blow a vivifying breath. 

 Astonished, he now finds that the touch of a finger elicits a responsive 

 note, and he hesitates, half delighted, half afirightcd, least he be 

 deafened by the chords which it would seem he can now summon forth 

 almost at will. 



[O.L.] 



