436 Official Correspondence on the attaching of 



sixty feet interval between conductors no accident can happen, falsified 

 by the above fact; since the window bolts constituted an imperfect 

 conductor within twenty feet, and no satisfactory conclusion on the 

 point can therefore be drawn.* 



* Note.— We have taken it for granted above that the distance of Mr. Trower's conduc- 

 tor from Dr. Goodeve's house has been correctly stated by Dr. O'Shaughnessy, but we acknow- 

 ledge that considerable doubt on this point has been excited in our mind, and as in inquiries 

 like the present, statements cannot be too rigidly scrutinised, we have thought it right to 

 allude to the grounds of this doubt. In its present position Mr. Trower's conductor is we 

 believe not less that 35 feet distant from the nearest part of Dr. Goodeve's house, and we 

 cannot estimate its distance from the window at the corresponding angle on which the dis- 

 charge struck at less than from 55 to 60 feet. Not having the means of verifying these dis- 

 tances by actual measurement, we regret much that the diagram alluded to by Dr. O'Shaugh- 

 nessy has not been published, since from that, if it has been drawn to a scale, as every such 

 drawing certainly ought to be, we might have satisfied our doubts immediately. Of course 

 if there is so great a difference between the actual distances and that specified by Dr. 

 O'Shaughnessy, as on good grounds we suspect there is, the whole course of his reasoning 

 on the case of Dr. Goodeve's house is essentially vitiated, and the conclusions he has based 

 upon it necessarily fall to the ground. It would be well if a drawing exhibiting correctly 

 the relative positions of the two houses were to be prepared, as any inferences on the case 

 would then be received with more confidence ; but judging from our own acquaintance with 

 the premises, we should be inclined to consider it next to impossible for the lightning to 

 have quitted Mr. Trower's conductor to strike upon the window bolts, without leaving some 

 indications of its course, as it must have traversed the Venetians of the verandah part of 

 the angle of Dr. Goodeve's house. And as we believe no such indications were given, we 

 are very doubtful if there is any warrant whatever to be derived from this case for Dr. 

 O'Shaughnessy's opinion, that occasionally " in tropical climates there is such a vast dispro- 

 portion between the quantity or intensity of electricity and tlie capacity of conductors, that 

 this excess of the discharge must pass to adjacent objects." The course of the lightning 

 after impact on Dr. Goodeve's house was to be traced by the fusion of the ends of the 

 window bolts, all of which we presume exhibited appearances like those represented in Dr. 

 O'Shaughnessy's sketch, and some such undoubted evidence as this fusion affords is necessary, 

 we conceive, to establish beyond dispute the true course of the lightning, since the dazzling 

 effect of the accompanying flash, and the natural confusion caused by the discharge, must 

 always tend to incapacitate an eye witness for giving a perfectly trustworthy account of 

 an accident ; and if but one individual witnessed the discharge, his opinion as to its having 

 impinged on anj r particular spot must be received with considerable caution. Unless Mr. 

 Trower's conductor gives some indication of the lightning having passed through it, we 

 conceive Dr. Goodeve's assertion that the lightning struck upon it still requires confirmation.* 

 On farther consideration of the circumstances of the case under discussion, it appears to 

 us that so far from " falsifying" Biot's opinion, it is calculated to afford it signal confirma- 

 tion. No accident whatever occurred in the interval between the perfect conductor on Mr- 

 Trower's house and the imperfect one formed by the window bolts of Dr. Goodeve's, although 

 the distance of the two was not much less than 60 feet; and as the only damage which happened 

 arose from the want of metallic continuity in the path chosen by the lightning, we cannot 

 but express our strong conviction, that had Dr. Goodeve's house possessed a well construct- 

 ed conductor it would have escaped uninjured. This impression is strengthened from the 

 efficiency of Mr. Trower's conductor, which though very far from being what we consider 

 faultless in its construction, seeing it is of iron, and only about an inch in diameter at its 

 base, was certainly the means of saving the house under its protection, by opening up a 

 continuous path by which the lightning falling upon it might pass to the earth. 



* Note by the Editor,—" Can you see lightning strike ?" This is one of the questions dis- 

 cussed by M. Arago, who decides in the negative. — Ed. 



