Intelligence and Miscellaneous Articles, 445 



sation of the aether occurring inside the trunk of the tree and 

 exploding (laterally all round) outwards with the velocity of light, 

 the trunk is shivered into fibres. In fact this is the exact effect 

 that might be expected from the above conditions. The aether may 

 of course in its normal state exercise very great pressure (many 

 tons on the square inch). 



The passage from ' Nature ' describing the observation of Prof. 

 Colladon may be appended here ; viz. : — 



" The Professor contends that it (the lightning) falls in a shower, 

 not in a particular flash, and that it runs along branches of trees 

 until it is all gathered in the trunk, which it twists or tears open in 

 its effort to reach the ground, In the instance in question, the 

 trunk of the cherry-tree is as completely shivered as if it had been 

 exploded by a charge of dynamite " (p. 204). 



The italicised passage tends to show a radial * (wave) movement 

 of matter from all sides simultaneously, or is consistent therewith. 

 It seems to be popularly suposed that the movement of matter is 

 propulsively along the line of flash (not sideways or radially towards 

 where the flash shows itself) ; this is why, no doubt, according to 

 the popular motion, it becomes utterly impossible to form a 

 mechanical idea as to how such destructive effects are produced by 

 lightning. 



The above suggestion makes no pretention to exactness or pre- 

 cision as to the modus operandi of a lightning discharge. There 

 are reasons, however, for believing that the idea is true on certain 

 broad or fundamental points (on account of its apparent mechanical 

 fitness); and the idea may invite others to reflect on the subject, 

 which can conduce to progress. 



As regards the " attraction " produced by vibration, the phe- 

 nomenon of "resonance" &c, the writer may mention briefly 

 some experiments made by himself some seven years ago. The 

 object was to augment the effects of attraction by trying the 

 influence of larger vibrating bodies than had hitherto been done. 

 Por this purpose, tuning-forks weighing some four to five pounds 

 each were taken. When such a fork was thrown into vibration 

 by a blow, it was found possible to suspend floating in the 

 air below the prong, pieces of cardboard, upwards of 4 inches 

 long, T inch wide, and about y 1 ^- inch thick. This therefore being 

 so distinct and palpable an instance of attraction by vibration or 

 resonance, may have interest especially in reference to the recent 

 experimental confirmation of the fact that static electricity (which 

 can " attract ") is also a phenomenon of " resonance." 



Hamburg, Jan. 1891. 



* Although the case is not strictly parallel, of course, a wave-movement 

 of the aether sideways towards a line may he seen in the line-focus of a 

 cylindrical lens. 



