492 Official Correspondence on the attaching of 



expressed. The mere testimony of eye-witnesses as to the 

 points of impact or course of an electric discharge we con- 

 sider of the least possible value ; and while the only proof 

 of impact on Mr. Trower's conductor was such testimony, 

 and from a solitary individual, it was impossible for us to 

 express ourselves satisfied. Our opinion as to the value of 

 ocular testimony was expressed in entire ignorance of M. 

 Arago's sentiments on the point, as we have not yet had an 

 opportunity of seeing his celebrated essay ; and since Dr. 

 O'Shaughnessy disputes the translation Dr. McClelland has 

 given of the question, which would prove he agreed with 

 us, we cannot yet appeal to his authority in support of our 

 views.* 



Imperfect as are the details connected with the Hccident 

 to the Purfleet magazine, with which Dr. O'Shaughnessy has 

 furnished us, they yet involve sufficient to shew that this 

 case forms no exception to Mr. Daniell's assertion, " that 

 there is no case on record of a properly protected maga- 

 zine having been struck by lightning." We are informed 

 that the discharge impinged on an iron cramp in the roof 

 of the magazine, the presence of which of itself is sufficient 

 to shew that the building was not properly constructed, 

 nor could its conductor act efficiently with metal in its 

 immediate vicinity. 



We considered Dr. O'Shaughnessy pledged to the accuracy 

 of every fact he had admitted into his papers, and finding 

 it there stated as a fact, that the spear head of the Bri- 

 tannia on Government House was fused by the discharge on 

 the 30th March, 1838, while we had good reason to doubt 

 it, we could not avoid allusion to the circumstance. Had 

 the spear point really been fused, the fact would have been 

 fatal to our preconceived opinion as to the course of the 

 lightning on that occasion, and we therefore felt an addi- 

 tional interest in having the truth discovered. 



* See Note p. 501. 



