310 London Electrical Society. 



LONDON ELECTRICAL SOCIETY. 



[Continued from p. 64.] 

 July 19*. — The Society assembled for the first time in its new 

 apartments in Cavendish Square. The following papers were read : — 



1 . " On the Solution of Gold in Muriatic Acid by Voltaic Agency." 

 By H. Prater, Esq., Memb. 



2. " On the Action of Lightning Conductors." By Mr. Charles 

 V. Walker, Hon. Sec. 



Having introduced the subject by referring to his observations on the 

 lightning-flash at Brixton Church (vide Phil. Mag. for July, p. 63.), 

 the author states that a series of recent experiments have rather 

 tended to confirm than change his opinion upon the phenomena 

 termed often "lateral discharge;" and that his present object is to 

 direct the attention of the Society to certain facts, which have not 

 been so prominently regarded as their nature demands ; and here 

 especial allusion is made to the Leyden discharge. That this dis- 

 charge is often employed in illustrating the action of lightning is 

 manifest to all who have paid any attention to the matter, and that 

 a large portion of the experiments, which have given rise to so much 

 difference of opinion, are the effects of Leyden discharges, is like- 

 wise well known. 



Mr. Walker commences by endeavouring to show the difference 

 between such discharge and a flash of lightning : he states, that sup- 

 posing a cloud to resemble one coating of a jar, the air to corre- 

 spond with the glass, and the earth with the other coating, the 

 discharge of that cloud is directly between the coatings, viz. through 

 the insulator ; and he then shows that a Leyden discharge only re- 

 sembles this, when it is of force sufficient to perforate the glass. He 

 explains that the regular discharge is operated upon by two forces 

 acting counter to each other ; the one directly between the two 

 coatings in direction a, the other between the discharging balls in 

 a direction b ; and that the length of shock, or as it is termed striking 

 distance, is the difference between these forces : when a — b represent 

 the resultant, the glass is perforated ; when b— a is the equivalent, 

 the regular discharge occurs. That this explanation is not imaginary, 

 is shown by comparing the striking distance of the Leyden discharge 

 with that from the prime conductor. With the Polytechnic battery, 

 containing 70 feet of coated glass, the distance is about one inch, 

 while from the large conductor of the machine sparks upwards of 

 two feet long will appear. He then calls into requisition the ocular 

 illustration of difference ; when one spark is direct and compact, the 

 other is long and zigzag ; and this leads him to point out the re- 

 semblance between lightning flashes and sparks from the conduct- 

 or ; not merely in their visible and accidental characters, but in 

 their passing just as lightning does, directly from a charged body to- 

 wards the earth in the direction of least resistance. Having shown 



* The papers read before the Society in April, omitted to be noticed in 

 our last, will be found in the Proceedings, Part V. 



