Explosive Effect of Electrical Discharges. 



281 



was obtained by stretching a fine wire over a photographic 

 film ami sending a single discharge through the wire, there 

 being no spark-gap in the circuit. The fine wire vibrated 

 during the discharge ; and when the negative thus obtained 

 was closely examined, subsidiary vibrations were shown by 

 many black lines approximately parallel to each other. These 

 lines were apparently caused by the heat of the discharge 

 melting the gelatine where the wire came in close contact 

 with the film. The electrostatic field about the wire is 

 exhibited by a fern-like discharge at right angles to the wire. 

 We were soon convinced that heat played a subordinate 

 part in the phenomenon shown by the quick rise of the 

 manometer-index. This rise was apparently dependent upon 

 electrostatic conditions rather than upon thermodynamic or 

 magnetic phenomena. AVe therefore abandoned the fine wire 



10,000 Plante cells, 150 condensers, charged in multiple and discharged 

 in series. Pointed brass terminals in large glass cylinder. Gauge 

 consisting of a bent glass tube with a potassium bichromate index. 

 Rj and R 2 readings of gauge before and after discharge. D difference 

 of these readings in centimetres. F distance between terminals. 



F. 



R r 



R, 



D. 



Average. 



F. 



R r 



R 2 . 



D. 



1-5 

 1-6 

 22 

 26 

 19 

 24 

 23 



Average. 

 21 



10 ... 



44 

 4 6 



49 



5-0 



04 



0-45 



60 ... 



67 ... 



! ., ••• 



i " ••• 



4-7 

 57 

 54 

 55 

 52 

 5-2 

 52 



4-8 

 51 

 53 

 55 

 52 

 5-4 

 55 



62 

 73 

 7-6 

 81 

 7-1 

 7-6 

 7-5 



70 



71 

 73 

 6 7 

 71 

 73 

 76 



17 ... 



,, 

 ,, 

 j, . .. 



45 

 47 

 4-8 

 50 



55 

 5-2 

 5-5 

 62 



10 

 5 

 07 

 1-2 



09 

 1-2 



24 ... 



4-7 

 50 

 53 



60 

 62 

 65 



13 

 12 

 1-2 



22 



20 

 20 

 1-2 

 1-9 



1-9 

 21 



1-9 



31 .. 



4-8 

 4-8 

 54 



67 

 66 



7-2 



1-9 



1-8 

 1-8 



1-8 



38 ... 



47 

 51 

 55 



6-7 

 73 



77 



20 

 2-2 



22 



24 

 24 



24 



22 

 23 



27 

 19 

 21 



21 



24 



i 74 



4-8 

 51 

 53 

 5 3 

 54 

 55 



6 4 

 66 

 69 



7 3 

 7-2 

 7-3 



1-6 

 1-5 

 1-6 

 20 



1-8 

 1-8 



17 



46 ... 

 53 ... 



}■) ••• 

 91 ••• 



4-8 

 53 

 5-5 



72 



7-7 

 7-9 



73 



7-7 

 73 

 71 

 75 



80 ... 



4-8 

 4-5 

 50 

 51 



52 

 63 



5-9 

 54 



04 

 1-8 

 09 

 0-3 



11 



51 

 54 

 56 

 5-2 

 54 



22 



