540 Proceedings. 



Eighth Meeting : 18th January, 1893. 



Sir Walter Buller, President, in the chair. 



Papers. — 1. " On Eainbows caused by Eeflection in Still 

 Water, and on Elliptical Eainbows," by Major - General 

 Schaw, C.B., E.E. {Transactions, p. 450.) 



Sir James Hector said that this was a most interesting paper. Pew 

 persons would imagine that there was so much to be learned on the sub- 

 ject of rainbows, and there was much in the paper that was quite new 

 and had not been previously observed. 



Mr. Harding was glad he had brought the subject forward at a pre- 

 vious meeting, as it had had the effect of bringing out such an admirable 

 paper as General Schaw's ; and he was glad to receive confirmation 

 of his view that a reflected rainbow could be seen, although not the 

 one visible to the eye. He hardly thought that the tertiary bow was 

 accounted for in the paper. 



Mr. C. Tanner referred to experiments he had made with a garden- 

 hose, which gave complete circular bows. 



Mr. Maskell was pleased that his question at the last meeting as to 

 whether a rainbow could be reflected in the water had been the means of 

 producing such an excellent paper as they had just listened to. It was 

 evident that the painter he referred to had made a mistake in his draw- 

 ing, for it was clear to him now that the reflection of a bow could be 

 seen, but not that of the actual bow observed. 



Mr. Richardson said there was a gentleman now in the room who 

 had seen the reflection of a rainbow, and he would no doubt give a de- 

 scription of it. 



Mr. A. Koch then said that on the 29th June last, about 10 a.m., on 

 board the cable-steamer " Terranora," anchored off the pilot-station, in 

 Worser Bay, his attention was excited by a very brilliant rainbow, forming 

 a complete semicircle. It started about the back of the pilot-house, and 

 continued its direction above the Pinnacle Rock, descending into the sea 

 about half a mile from the eastern shore of the entrance to Wel- 

 lington Harbour. The sea was without a ripple, a steady rain falling, 

 and both sea and distant headlands of a deep slate-colour. The rainbow 

 left a distinct and brilliant-coloured reflection upon the sea ; and, having 

 called the attention of some other gentlemen on board, an additional fact 

 was observed, which none of us could explain — viz., that the reflection 

 did not commence at the point at which the rainbow dipped into the 

 sea, but started about 10 chains inside the semicircle formed by the 

 rainbow. As doubts had been expressed on rainbow reflections, he was 

 glad he had sketched this one (see PI. LI.). 



Sir Walter Buller said that, inasmuch as the rainbow appearance was 

 due to the angle of incidence, and was governed by the laws of optics, it 

 seemed to him that, technically, no two persons looking at the same time, 

 but necessarily at different angles of vision, could see the same rainbow, 

 so that, in truth, each pair of eyes had its own rainbow. He had seen 

 perfect lunar rainbows, either colourless or with an extremely faint tint. 

 The most remarkable one he had seen was at the Chatham Islands in 

 1855, and, if he could trust his memory, it was attended by a very pale 

 secondary bow. The most beautiful solar rainbow he had ever seen was 

 one projected on the cloud of fine spray at the Palls of Niagara in 1874. 



Mr. G. Beetham had more than once seen a true lunar rainbow in 

 New Zealand suffused with a pale colour like a faded solar rainbow. 



Major-General Schaw said that the tertiary bow was formed by the 

 third reflection. It was not often seen. He also said that the observa- 

 tion by Mr. Koch of a reflected rainbow was extremely interesting, as it 



