and the effects of lightning on H,M.S. Rodney^ ^x. 1 17 



phEenomenon in electricity, termed by Cavallo, Priestley, and 

 others the lateral explosion, and showed that it did not apply 

 to the state of a metallic rod in the act of transmitting a va- 

 nishing electrical accumulation between two opposed electri- 

 fied surfaces, as insisted on by Mr. Sturgeon in a recent num- 

 ber of his Annals of Electricity. I will now proceed to ex- 

 amine the general character and effect of ordinary electrical 

 discharges, whether produced on the great scale of nature, 

 or artificially, with a view of fiirther showing, that such lateral 

 explosions do not occur at the instant of the passing of a 

 shock of lightning through a metallic conductor, as also with 

 a view of meeting certain other objections which have been ad- 

 vanced at different times to the use of lightning rods in ships, 



2. I should not have felt myself called upon to notice fur- 

 ther Mr. Sturgeon's memoir, did I not consider the state- 

 ments it contains, although superficial and inconclusive, likely 

 to mislead the public upon many important points connected 

 with the effectual protection of shipping against the destructive 

 effects of lightning, and convey false views of the nature of 

 electrical action. Under these impressions I have little hesi- 

 tation in noticing what he has advanced under the following 

 heads : — 



1st. Examination of the observed effects produced on 

 shipping by lightning. 



2nd. A comparison of the observed effects of lightning 

 and the probable effects which lightning v\ould pro- 

 duce by the application of Mr. Harris's conductors to 

 shipping. 



3. The first contains an excellent, and I have no doubt, an 

 accurate statement, by an intelligent officer of the Rodney, of 

 the destructive effects of lightning lately experienced in that 

 ship, together with notices of two cases in which ships fitted 

 with my conductors were struck by lightning without any 

 attendant ill consequence. In the second, it is the author's 

 object to prove, from the effects of lightning in the Rodney, 

 that my system is inadmissible; since the discharge of light- 

 ning, he observes, which struck the Rodney, " would have 

 been powerful enough to have rendered even the thickest 

 part of Mr. Harris's conductors sufficiently hot to ignite gun- 

 powder." 



Considering the boldness of this assertion, and the high 

 pretension of the memoir, we should expect, on examining 

 the author's researches, to find him in possession of a copious 

 induction of facts from well-authenticated cases of damage by 

 lightning on ship-board, illustrating clearly the views he so 

 strenuously insists on, — cases in which continuous or other 



