322 APPENDIX. [No. XXIII. 



within five minutes we were in comparative darkness, when the most 

 terrific flashes of lightning occurred, accompanied with peals of thunder. 

 This was followed almost simultaneously by enormous hailstones, so thick 

 that we could scarcely see a few yards before us. We had great difficulty 

 in proceeding to the nearest house, which was scarcely a hundred yards, 

 and it was only after incessant ringing, that one of the inmates ventured 

 out to open the gate to give us shelter. 



In this case there was manifestly an instantaneous and rapid deve- 

 lopment of new attractions in the aggregation of aqueous vapour into 

 large hailstones, and I believe that aggregation of vapour acting upon 

 the attracted matter of the clouds is the true source of the electric 

 development. 



The sublime phenomenon of the thunder-cloud I have watched as it 

 plays over the ocean's bed ; I have been in the midst of it at the top of the 

 mountain, I have seen it hoveling over the lake, and heard the thunder 

 reverberate from shore to shore of the castle-bearing hills of the Rhine, 

 yet it is worthy of mention that in no place has it been so grand as in this 

 Circus during the stillness of night. Here we have a multiple echo, and 

 when the cloud is overhead, the crash is reverberated from side to side with 

 a majesty unequalled by any other natural phenomenon, and which well 

 marks the power which is acting during the electric discharge. 



The capacity to produce action is called force, and, whenever a new 

 attraction is set up, force results. Force differs from tension in being 

 able to do that which tension is prevented, by a resistance, from accom- 

 plishing. Any kind of attraction gives rise to force. The attraction of 

 gravitation, capillary attraction, the attraction of aggregation, or of 

 chemical affinity, will produce force. 



When a new attraction is exerted, the force emanating therefrom may 

 be propagated through aeriform bodies, when it is termed pneumatic 

 force ; through fluid bodies, when it is called hydrostatic force ; through 

 solid bodies, when it is called mechanical force. 



I have heard it stated that whenever force is generated it is never 

 annihilated. To such an extraordinary proposition my system not only 

 gives an unqualified denial, but points out the manner in which force 

 comes to an end. However long it may endure, however many bodies it 

 may pass through, its final action is to destroy some pre-existing attrac- 

 tion, and either disintegrate, decompose, or move previously attracted 

 matter. 



The resistance of matter under attraction to a new attraction leads to 

 the production of various phenomena. Under certain circumstances, that 

 which we call heat is evinced. For heat, it is necessary that a resistance 

 to the new attraction should be afforded by the pre-existing attraction. 

 In the voltaic circuit, if any part is contracted heat is manifested, and in 

 this way water may be boiled, or platinum (one of the most infusible of 

 substances) may be made to fuse like wax. Mechanical force causes heat, 

 when applied to solid bodies ; and whenever attraction acts with sufficient 

 energy upon attracted matter, heat results. Where we require intense 

 heat we must employ an intense new attraction on an intense aggregation, 

 and hence every practical man uses light or strong coke according to the 

 intensity of heat he requires. Whilst heat exists, the new attraction is 

 merely attempting to destroy other attractions, and the force may be 



