40 



SCIENCE. 



[Vol. XXII. No. 546 



It is well known in various countries tbat fishes swim up to a 

 boat on a stream if a light is displayed on board. 



An interesting spectacle is produced if a candle, or better still 

 an electric glow lamp is brought near the glass sides of an 

 aquarium. Fishes, aquatic larrae and mullusca swim np and 

 seek to come as near as possible to the light. 



Numbers of nocturnal insects are attracted by flame. Moths, 

 gnats, crane-flies and many other dipteia are noted for their pro- 

 pensity to commit suicide in our lamps and candles. Many of 

 the smaller moths are found sitting on the glasses or the iron 

 frame work of stivet-lamps. I have known an old lady made ill 

 with fright because a. i^ieath's-bead (Acherontiaatropos) had flown 

 against her candle and put it out. 



But we must now glance at the main question, that is, the 

 meaning of the behavior of nocturnal animals in presence of a 

 light. The iilarm of many species is not hard to understand. 

 A bright light is a phenomenon which does not fall within the 

 limits of their experience and seems lo them, therefore some- 

 thing to be avoidfd. But to see nocturnal, abysmal or cave- 

 dwelling species flocking to a light is perplexing. 



It has been suggested that the moth thinks the flame an outlet 

 through which it may escape. But why should it seek to escape 

 from a condition which to it is as normal as is sunlight to the 

 butterfly or to the bee ? It has again been suggested that noctur- 

 nal insects and fishes are able to preceive the faint phosphorescent 

 light apparently given off by many flowers, and by aquatic 

 worms, etc. Hence the moth rushes to the lamp mistaking it for 

 a flower. On coming nearer he is bewildered by the intensity of 

 the light and " loses his head." This same supposition explains 

 why mosquitoes are less attracted by a lamp than are most other 

 insects. They are not accustomed to find their food in phos- 

 phorescent flowers, hence the lamp has to them little attraction. 



True, this hypothesis fails to show why birds should dash them- 

 selves against the windows of a lighthouse. Their normal food 

 is not phosphorescent. Nor. to our knowledge, are their eyes 

 capable of perceiving a faint phosphorescent light. 



Probably no single hypothesis will meet all the cases of the at- 

 traction of animals to light. ^ J. W. Slater. 



London, England. 



The Aurora. ' 



The contradiction in certain statements of mine with reference 

 to the possibility of tracing the relation of the aurora to disturb- 

 ances upon a particular part of the sun in certain years which 

 Professor Ashe thinks he has delected and which he puts into 

 italics at page 9 of Science for July 7 amounts to simply this: 

 In one sentence which he quotes I am giving the reason why the 

 relation in question comes out distinctly in years of minimum, 

 namely, because the disturbances are well separated from each- 

 other, and, taking 1879 as an example, show by a table that this 

 was the case in that year, in which both auroras and sunspots 

 were so very few that the numbers to be employed were so ex- 

 tremely small that it might justly be doubted whether they show 

 anything, and yet, in spite of this disadvantage, namely, the 

 smallness of the numbers, the relation was plainly apparent. In 

 another sentence, referring to the matter from this point of view, 

 namely, the size of the numbers to be employed, I state that in. 

 1880 the relation in this respect would be much more distinct, 

 this also being a year of comparative minimum in which the dis- 

 turbances were well separated from each other, so that the con- 

 clusion with reference to this year contained in the sentence 

 which Professor Asche quotes would be fully justified, i.e., " the 

 numbers would be larger and the relation in every way more dis- 

 tinct." The only reason for the publication of the table for 187ft 

 was to show what would appear in the year in which we might 

 suppose the relation exceptionally difBcult to trace and jet in 

 which it was distinctly apparent in spite of the, smallness of the 

 numbers. It was simply picking out the worst possible case, as 

 we would naturally suppose, instead of the best possible case,, 

 and it is to its discussion that the sentences which Professor 

 Ashe quotes, refer. M. A. Veeder. 



Lyons, N. Y., July 13. 



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THE MODERN MALADY ; or, Suf- 

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An iutroductioti to public consideration, 

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