SCIENCE-GOSSIP. 



233 



RAINBOW WONDERS OF 

 "WINDERMERE. 



A N article under the above heading appeared 

 in the London " Daily Telegraph " of 12th 

 October last. A friend of mine witnessed the 

 phenomenon on the same day as the writer of 

 the article, viz., Wednesday, October 5th, and 

 was unable to account for it. He thinks the area 

 of iridescence was too extensive to have been 

 caused by trade refuse, and there was no steamer on 

 the lake at the time. 



The following is an extract from the article 

 referred to : — 



" There was no ripple on the mere, and when we 

 pushed out into middle lake so marvellous were 

 the reflections of fell and wood, so transparent the 

 depths, that one could hardly tell whether we were 

 upon water or suspended in middle air. Suddenly 

 my companion cried, ' Look at the rainbows ! ' 

 Gazing south towards Belle Isle, one saw the 

 whole water iris-hued, as if all the rainbows that 

 had ever sprung from earth to heaven had melted 

 into the bosom of the lake and filled the sunny 

 depth with liquid iridescence. 



" Slowly we rowed towards them, and the rain- 

 bows stayed for us till our boat pushed into the 

 lucent flood, and then as we moved forward, on 

 either side our wake, the rainbows curved and 

 quivered and sprang like horns of multi-coloured 

 light to right and left, and lengthening out, shone 

 far astern. On we went, wondering at the 

 glory and the glow. Our boat's motion seemed 

 momentarily to kill the marvellous prismatic flood, 

 but it was only for a moment that the rainbows 

 faded, and again, beyond the ripple and the washing 

 of our oars, there sprang into being new rainbow- 

 tinctured beauty of liquid purple, shot with green 

 and orange and rose, and behind us as well as 

 before us the lake mirror lay, one mighty opal, one 

 flood of lucent pearl and fire. 



" Beyond the rainbow lustres far away the lake 

 seemed to have been silvered over with frost. One 

 could have staked one's life, unless one's eyes were 

 playing false, that the ice-king had been at work, 

 and the thin ice-mirrors he had made were powdered 

 with the hoary rime. But as one neared it the 

 phantom ice-floe faded, and nothing but liquid 

 rainbows for the keel to cleave and fashion again 

 to wondrous loveliness, and the finest dust-like 

 floating meal, remained, where before we might 

 have supposed was a fair field for the skater's joy 

 and curler's game. It was rainbows, rainbows all 

 the way ; and what was the cause of this October 

 glory of rainbow flood ? It was nothing in the 

 world but a smooth lake surface, and the fine dust 

 of pollen of the American water-weed Vallisneria. 

 Others aver it is the gold dust of the water lobelia, 

 which, floating upward through the tranquil water 

 on a calm October day, lies on the surface of the 

 polished lake mirror with power to change the 

 face of the water into such a refracting and dif- 

 fracting medium as to splinter all the sun into 

 iridescence, and unravel the beam of white light 

 into the colours of the prism. 



"It would seem that the water must be of a 

 certain temperature to encourage the plant to send 

 forth its prism-makers to the surface. It is certain 

 that no breath in heaven must stir if the lake- 

 mirror is to work its magic charm. Only on rare 

 days, such as was October 5th, could Windermere 



be clad in rainbow hue. One may live by the 

 shore of the lake for another fifteen years before 

 one may be fortunate enough to witness again 

 the glorious phenomenon, or be privileged to push 

 one's shallop through a league of liquid iris, or 

 sail through miles of rainbow." 



Now the scientific explanation as above given 

 is open to the following objections. Vallisneria, 

 which is not the American water-weed, does 

 not grow in English lakes. Elodea canadensis (the 

 American water-weed) does not yield pollen in 

 England, only the female plant having been 

 introduced into this country. Lobelia dortmanna 

 (water lobelia) does not probably grow in sufficient 

 quantities, and blooms earlier in the season. 

 As, however, the description of " finest dust- 

 like floating meal " seems to accord with the idea 

 of pollen rather than with that of tar-oil, which 

 has also been suggested to me, I should be glad 

 if you, or one of your scientific correspondents, 

 would express an opinion as to the length of time 

 that the pollen of the water lobelia, or other water 

 plant, say Potamogeton, would remain after pollina- 

 tion on the surface of the lake, and whether the 

 iridescence could be attributable so late in the 

 season to such a cause. 



If not, is there any seed of plant, or spore of fern 



or moss, or freshwater alga, which would produce 



the effect described ? In the " Natural History of 



Plants " (Kerner and Oliver, vol. ii. p. 621) there 



occurs under the head Cyanophyceae, sub-head 



Nostocaceae, the following passage : — " Very little 



is really known about the life-histories of these 



interesting plants, which so frequently appear in 



great quantities on or near the surface of the water 



and then as mysteriously disappear." 



M. J. Teesdale. 



St. Margaret's. Thwlow Park Road, 

 West Dulwich, S.E. 



[This rare phenomenon was observed on the 

 surface of Lake Windermere in 1851, also about 

 1874, likewise on Derwentwater in the same year, 

 and on Loch Lomond in 1853. See Science- 

 Gossip N.S., vol. i. pp. 90 and 165. — Ed. S.-G.] 



Vernacular Names. — The editors of the "Natu- 

 ralist " are collecting vernacular names used in the 

 Northern counties for animals common in these 

 districts. We do not observe many which are 

 new to us, though some are unfamiliar, such as 

 " twitch-bells," or " furking robins," local names 

 in East Yorkshire for earwigs. In the same 

 district " tommy tailors " is used for daddylong- 

 legs, and " artystraws " for shrews. " Foumart," 

 as applied to a stoat, must, we think, be an 

 error, as it is the usual name in the North for the 

 marten, which was by no means uncommon half 

 a century ago in Lancashire and Yorkshire, 

 where the expression "stinks like a foumart" 

 is still frequently used. 



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