2/8 On Lightning Conductors to Powder Magazines. [No. 99. 



(No. l.J 

 To Dr. O'Shaughnessy, 



Medical College. 



Ordnance Department. 



Sir, 

 The Military Board having been called upon by Government 

 to report upon the expediency or otherwise of attaching light- 

 ning conductors to powder magazines, I have been instructed 

 to address you on the subject, in the hope that your scientific 

 knowledge may assist the Board in forming a correct opinion 

 on that point. 



2. Should the use of lightning conductors be considered 

 by you desirable, the Board would feel obliged by any sug- 

 gestions that you may be able to offer as to their height, 

 position, size, and number for any given extent of horizontal 

 or vertical surface. 



3. The accompanying memorandum was received from the 

 Court of Directors, and you are requested to return it with your 

 reply. 



Fort William, * 



Military Board Office, Your obedient servant, 



22nd December, 1838. w Debude ^ 



Officiating Secretary Military Board. 



(Memoran dum .) 



The higher a conductor is elevated, the more its efficacy 

 will be increased. 



Therefore for a powder magazine the conducting rod should 

 be elevated seven feet at the least above the highest point of 

 the building; should be placed standing out one foot from 

 the building, and be made as continuous and direct as possible, 

 branching out at the level of the ground, and carried under 

 ground in a dry brick drain six inches diameter, ten feet long, 

 from thence carried down a hole filled with burnt charcoal, 

 or ashes from the baker's oven. 



Copper rods pointed at top with platina are recommended. 



