THE THUNDERSTORM OF OCTOBER 26. 1888. 339 



on the anomometer shews a fall of 0*15, the same as the standard 

 barograph. Under ordinary conditions such a rapid change of 

 pressure would be accompanied by very violent wind, but on this 

 occasion although there was a squall in which the wind rose to 40 

 miles per hour, it did not last five minutes, and as a whole the 

 storm brought very little wind or rain, its distinctive feature 

 apart from the extraordinary barometric change being the intense 

 electrical discharges. Some of these were brilliantly white bands 

 60° and even 70° long, and they gave a dazzling light that 

 illuminated the whole city to such an extent that the photograph 

 I took of one of them shews the outline of the houses from the 

 momentary light of a single flash ; , and another plate which was 

 exposed for five minutes waiting for a flash in a particular direction 

 has on it a picture of lower Fort Street, the Harbour and North 

 Shore by the light of flashes which were outside the field of the 

 camera, and on the negative the outline of some clouds can be 

 made out distinctly. The first photograph referred to is exhibited 

 and shews clearly that there were a number of lateral discharges 

 from the flash, and it is much more brilliant high up than near 

 the horizon, this may however be due to the nearness of the upper 

 part compared with that near the horizon. The second photograph 

 shews a similar flash evidently much more distant, and near it 

 can be faintly seen one of the curious zigzag flashes that were so 

 frequent between the clouds. This is faint, because like most 

 of them were, it was apparently in a mist ; that is seen through 

 a cloud, and in addition had a yellowish colour unfavourable for 

 photography. It will be observed that the brighter flash on this 

 photograph is double for a considerable part of its length, and just 

 before it, I saw one for which the camera was not ready, which 

 was double from top to bottom, ■i.e. over a length of about 70°. 

 The rain although not heavy prevented me from getting photographs 

 of some of the flashes because it wet the lenses, and I was 

 obliged to get what I could through an opening in the dome. 



The majority of the lightning flashes were between the clouds 

 and presented a curious wavy form often very beautiful, but all 

 of these that I saw seemed to be in a yellow mist, as if in the 

 clouds, while all the up and down strokes were brilliantly white, 

 and in number could not have been more than a quarter or one- 

 third of those in the clouds. 



The photograph shews clearly that the course of the brighter flash 

 was a very wavy one, like a ribbon blown by the wind ; and it 

 looks as if in some places its course had been in the direction of 

 the line of sight ; in these parts it would of course be more brilliant 

 from the fact that it was seen end on. This suggests a very 

 satisfactory explanation of a remarkable appearance which is 

 sometimes seen, and which I once observed in Sydney, that is, 



