TRANSACTIONS OF SECTION A. 609 



certainly say that iron would not be as g-ood as copper, because, as Sir James 

 Douglass bad pointed out, iron would not stand. It was not only a question of 

 tbe weather, but at the top of a chimney — for instance, at the top of a factory 

 chimney — the bricks are red-hot ; and in the case of iron works and other places 

 anybody who examined the top of an iron works chimney would see some material 

 there, some chemical deposit from the chimney, and he did not think that any 

 iron conductor could live in the face of that, otherwise he would say that there is 

 no difference between one and the other. 



Mr. Brown (of Belfast) suggested that if one were to use a revolving camera 

 successive flashes in the same path would be separated on the plate, and it would 

 be easy to calculate the time interval, knowing the rate at which the camera was 

 revolving. He had used a revolving camera himself for the purpose of registering, 

 and he might say from his experience that it would be quite easy to determine the 

 tenth of a second. In order to investigate the other question as to successive 

 flashes in different paths, that could easily be done by setting up one stationary 

 camera to photograph the thing in the ordinary way, having a secondary camera 

 revolving on a vertical axis, and comparing the photographs. 



Mr. Stmoxs said he ought perhaps to ofler some apology for speaking on this 

 subject, but the fact was that it was a thing to which he had devoted his attention 

 for considerably over thirty years. In fact, as far back as 1859 he was present 

 at a discussion on lightning-conductors, the one at which Su' William Thomson 

 made the very remark which had been referred to that day. He dared say Sir 

 William would remember the remark on that occasion, that when he suggested 

 to the Glasgow manufacturers to set up lightning-conductors they all said it was 

 ' cheaper to insure.' Lord Rayleigh said it was desirable to get the evidence of 

 practical men. He had nothing to do with the construction or the erection of 

 lightning-conductors, but all his life it had been a hobby of his own to investigate 

 every accident that he could possibly hear of involving damage by lightning ; and in 

 that way he had got, he supposed, experience which was certainly not theoretical, 

 but it was possibly of some value. Then eventually, when it came to be a question 

 of drawing- up this code of liofhtning-conductors, he was one of the Committee, and 

 they did him the honour of making him Secretary, and the consequence was he 

 had had a great deal of evidence brought before him ; and he must say that the 

 impression left upon his mind as the result of the whole of his experience was 

 precisely in accordance with that of Sir James Douglass, namely, that, as far as 

 they could judge, if people would only put up conductors precisely in accordance 

 with their rules, fulfilling all those conditions, those conductors were absolutely 

 safe. He had not a shadow of hesitation in saying so. He admitted that 

 accidents had happened now and then to buildings which had conductors, but a 

 reasonable explanation ot every one of those accidents to the best of his knowledge 

 was forthcoming. They all knew how very much easier it was to produce destruc- 

 tive criticism than constructive criticism. Professor Lodge's experiments (and he 

 yielded to no one in appreciation of him as an experimenter) were simply labora- 

 tory experiments after all, and it seemed to him that what they wanted was 

 something on an infinitely larger scale. He was not going to suggest how they 

 could make artificial lightning, so that they might deal with the actual thing 

 itself, although he must say that the idea had often occurred to him that a great 

 deal of information upon the subject could be obtained, if upon the summit of 

 some of those hills which they knew were most frequently struck, a series of inter- 

 rupted conductors were put up on tall masts where the lightning would pre- 

 sumably strike, and would strike of course without risk to human life, and they 

 might thus learn a good deal more than they knew at the present time. He 

 certainly did feel most desirous on the one hand that if possible a lightning-con- 

 ductor should be cheapened and rendered more generally accessible ; but on the 

 other hand that they should not simply on the strength (as he said before) of 

 those laboratory experiments allow to go forth from this great Association that 

 there was any uncertainty in the protection of the public buildings throughout the 

 country. It seemed to him that a very serious responsibility attached to those who- 

 would make a suggestion of that nature. They had experience, not only in this. 



1888. E E 



