481 



" Official Correspondence on the attaching of Lightning Con- 

 ductors to Powder Magazines"* 



[Asiatic Society's Journal, No. 99, 1840.] 



The papers under the above title, communicated to the current number 

 of the Asiatic Society's Journal by Dr. O'Shaughnessy, embrace the 

 discussion of a question of so much economical importance, and so 

 vitally connected with the welfare of our community, that we have been 

 induced to examine them in some detail, and under a sense of their 

 general interest, we have ventured to place before our readers the 

 following remarks upon them. The question of the efficiency of 

 Lightning Conductors to afford the requisite protection to Powder 

 Magazines during thunder-storms was brought under the notice of 

 Government in consequence of the explosion of the Magazine at Dum- 

 Dum, in June, 1836, from the effect of a stroke of lightning. The 

 Military Board were accordingly directed to report " on the expediency 

 or otherwise of attaching conductors to Powder Magazines;" and to 

 aid themselves in forming a correct opinion on the point, they applied 

 to Dr. O'Shaughnessy, and in due time received from that gentleman 

 a report unfavorable to the employment of conductors as usually 

 constructed and applied. The Government apparently desirous of 

 obtaining the opinions of some of the eminent Electricians at home, 

 forwarded the whole of the papers connected with the subject to the 

 Court of Directors, by whose instructions they were submitted to Dr. 

 Faraday, and Professor Daniell. The reports of these gentlemen are 

 published in full, and will be found most interesting and valuable, 

 embodying as they do the sentiments of two of the most eminent 

 Electricians of the present age. Their remarks follow generally the 

 course of Dr. O'Shaughnessy's original report (No. 2 of the series), and 

 as this gentleman classes under three heads, his reasons for consi- 

 dering it inexpedient to attach ordinary conductors to Powder Maga- 

 zines, we will first state these, and then follow Messrs. Faraday and 

 Daniell in their comments upon them. 



Dr. O'Shaughnessy's objections to the use of ordinary conductors on 

 Powder Magazines, are, 



1. Because being of slight elevation, of rounded surface, and of non- 

 conducting materials, these buildings are scarcely more exposed to 

 lightning, than an equal area of ordinary ground. 



* This communication, which is authenticated, was received from a correspondent 17th 

 August, 1S40.— Er>. 



