TRANSACTIONS OF SECTION A. 615 



occurred it was extremely disagreeaMe, and that they had better take example by 

 the old rule that ' absence of body ' is better than ' presence of mind ' and avoid 

 being near a flash if they could. 



He did not think there was any doubt, quite independent of any experiments 

 of Mr. Lodge's, that, as a matter of experience, lightning-conductors have protected 

 buildings, whatever the explanation of it is, nor that there was any doubt that we 

 have been right on the whole in our methods of erecting conductors. Perhaps 

 there are improvements po.-sible ; perhaps we might be able to protect ourselves 

 from those unfortunate discharges that occur in telephones, and so forth ; but, as a 

 whole, lightning-conductors have been a great protection to mankind from danger 

 by lightning. That is undoubtedly the residt of our experience. 



2. On the Burning li/ Lightning of a Magnet on a Generating Dynamo at 

 the Waterfall an the Bush Biver, County Antrim, helonging to the Giant's 

 Causeway and Portrush Electric Railway and Tramway Company. By 

 Anthony Teaill, LL.D., M.D. 



I happened last month to be travelling on this line in a thunderstorm. The 

 electric car was going well, at about twelve miles an hour, when I observed that 

 the main power of the current suddenly left us, and we were with difficulty able, 

 at a verv reduced speed, to finish our journey. On arriving at Bushmills 1 drove 

 up to the waterfall, on the river Bush, where the electric station is situated, 

 and there found that one of the magnets of the five-ton dynamo (Elwell- 

 Parker) had become short-circuited, the series wire and shunt wire having been 

 fused into each other, and the thick ply of all insulating material burnt up. The 

 turbine-driver stated that just at the moment of a heavy thunderclap there was a 

 tremendous flash of lightning all through the room, and the rupture of the magnet 

 took place at that instant. 



On a former occasion during a thunderstorm there was great consternation 

 both in the generating -room, where there were great flashes on the brushes of the 

 dynamo which were burned, and on the car, which was travelling on the line, 

 where the lightning seemed to plav all round the car for some moments, and 

 especially to flash on the brushes and about the starting commutator which puts 

 on or cuts ofi" the current from the car. The driver of the car was so alarmed as to 

 stop the car and jump off", but no injury was done to the car or to the motor 

 apparatus in it. 



Query : Should lightning-conductors be placed at the generating-station and 

 along the main line ? 



3. Analyse chronometrique des Phenomenes electriques lumineux. 

 Par Dr. J. Janssen. 



Le principe du revolver photographique propose par I'auteur en 1874 ii propos 

 du Passage de V(5nus, et qui a €i& applique depuis si heureusement par M. Marey 

 a I'analyse des mouvements du vol des oiseaux, pent donner egalement la solution 

 de divers problemes de physique et de m^canique, et notamment celui oil Ton se 

 propose d'analyser les circonstances de la propagation des phenomenes lumineux 

 dans les etincelles Electriques, les decharges, la foudre, etc. 



L'appareil consiste en une chambre photographique portant deux objectifs^ de 

 meme ouverture et foyer. L'un des objectifs donne les images sur tm disque aiiime 

 d'un mouvement de rotation rapide et portant une pellicule photographique sensible. 

 L'autre objectif donne les images sur une pellicule semblable mais fixe. 



Quand l'appareil est en mouvement on en excite r(5tincelle, ou bien si les 

 (5tincelles se succedent d'elles-memes on d^couvre un instant les objectifs. 



Deux images se forment ainsi, I'une sur le disque fixe, et celle-ci est I'lmage 

 normale, tandis que celle du disque mobile sera plus ou moins deform6e si le 

 phenomene ne s'est pas produit assez instantanement pour ne pas etre influence par 

 le mouvement. 



