Lightning Conductors to Powder Magazines, 491 



ferer. Dr. O'Shaughnessy states, that admitting the danger 

 from the lateral spark in a well stored Magazine, we propose 

 to do away entirely with the copper linings of the powder 

 barrels ; but he neglects to add, that this proposal was made 

 dependant on the possibility of substituting some non- 

 conducting substance for them. Cheerfully acquitting Dr. 

 O'Shaughnessy, as we do, of wilful misrepresentation either 

 in Mr. Daniell's case or our own, his failure in appre- 

 hending our meaning, and his entirely erroneous statement 

 of the nature of our suggestion (for it merits no higher title 

 in its present state) are matters not so much of complaint as 

 of surprise, since they indicate on his part a deficiency of 

 that perceptive power which is an element of primary im- 

 portance in the constitution of a scientific mind. The tri- 

 fling in which Dr. O'Shaughnessy has indulged on this point, 

 is unworthy at once of its author, and the subject under dis- 

 cussion ; and having shewn it to be based on a mistake, we 

 may consign it to that oblivion which best befits it. 



Having read both of Dr. O'Shaughnessy's papers with 

 the utmost attention we could command, we are at a loss to 

 understand what he means by saying, that the case of Dr. 

 Goodeve's house is therein referred to, especially in the 

 second paper, more for illustration than for proof. The op- 

 posite inference, we confess, would have suggested itself to 

 us, since we find it appealed to as a species of " crucial in- 

 stance" between his opinions and those of Mr. Daniell ; as 

 however Dr. O'Shaughnessy appears now inclined to esti- 

 mate the support to his opinions afforded, by this case at its 

 true value, we do not consider it necessary to dwell further 

 upon it. 



The information relative to the effect of the lightning on 

 Mr. Trower's conductor, contained in Dr. O'Shaughnessy's 

 reply to our remarks, removes satisfactorily our doubts as to 

 its having been struck at all ; and had it been furnished us 

 in the first instance, these doubts would never have been 



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