Lightning Conductors to Powder Magazines. 435 



so. Ordnance for the defence, ammunition, as shot and shells, tools, 

 and materials, for the construction of which metal is so largely employ- 

 ed, must always be at hand, and in the case of an actual attack, these 

 are usually concentrated in the immediate neighbourhood of the Maga- 

 zines, so that practically, the Magazine at Dum-Dum, except in its form 

 appears to us a fair representative of the class. That we are not now 

 speaking unadvisably in this respect, the actual circumstances under 

 which the Magazine in Fort William is at this moment placed, will 

 prove. We have examined it with reference to the subject under dis- 

 cussion, and have found that it is closely adjoining to a yard in which 

 upwards of a thousand feet of metallic boring rods with chains, guns, 

 crabs, and large quantities of iron tools, have been constantly kept for 

 the last four or five years. Some little distance in rear of it is another 

 yard with large quantities of metal in it, and again a little way in rear 

 of this is a large assemblage of iron guns. In the exposure to inductive 

 influence Fort William Magazine appears to rfs not at all inferior to 

 that at Dum-Dum, and though its elevation may be less, and its form 

 more rounded, yet if the explosion in the one case is attributable to the 

 presence of large quantities of metals, it seems not unreasonable to con- 

 clude that the safety in the other has been in some degree at least de- 

 pendent on the presence of the conductor, which we have been informed 

 has been attached to the building for eight years. 



Dr. O'Shaughnessy's second objection is based chiefly on the circum- 

 stances attendant on the accident to Dr. Goodeve's house, as he states 

 that this case seems to him to prove that occasionally in tropical cli- 

 matesj there is such a vast disproportion between the quantity or inten- 

 sity of the atmospheric electricity and the conducting "capacity of con- 

 ductors, that the excess must pass to adjacent bodies." This is a 

 generalisation far too extensive it appears to us to be justified by a 

 solitary fact, even if that fact were more favorable to it in all its at- 

 tendant circumstances than that before us is; but we coincide in 

 opinion with Mr. Daniell, that the case of Dr. Goodeve's house warrants 

 no inference more extensive than that the excess of electricity quits 

 the main conductor only to impinge on metallic bodies ; other facts are 

 necessary to warrant the wider conclusion that the excess quits the 

 conductor to impinge on all adjacent bodies. The electricity striking 

 Mr. Trower's conductor quitted it — if it quittedit at all (on which point 

 the information afforded appears to us inconclusive) — to strike the 

 window bolts only, and close induction will not admit of our inferring 

 from this circumstance that a like result will happen if no bolts or 

 other metallic fastening are present. Nor is Biot's opinion, that within 



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