34C? 



NATURE 



{Feb, 13, 1879 



the consideration of Mr. Mallet's experiments on cooling slag run 

 from an iron furnace.^ 



This coefficient is somewhat larger than the mean of those 

 obtained by Mr. Adie * for much lower temperatures. The mean 

 of six of his values, half of them being for moist rock and half 

 for dry, I find to be '0000057. 



Mr. Darwin recalls attention to M. Favre's experiments (out 

 of which the present correspondence arose). M. Favre's experi- 

 ments illustrate well the structure of an alpine district. But I 

 would observe that, if ours is a cooling solid globe, and if that 

 would give rise to such surface structure, we ought to find it 

 everywhere, and not confined to definite geographical areas, as 

 we do. O. Fisher 



Harlton, Cambridge, February 8 



Concerning the Colour of Eyes 



May a portrait painter be allowed to remark that there are 

 two kinds of green eyes, and the poets have duly appreciated 

 both. The eye of the "green-eyed monster" is, no doubt, the 

 cold grey, or stony blue eye, overspread with the yellow of 

 biliousness, hence green ; but when Dante called the eyes of the 

 beatified Beatrice emeralds he did not mean to insult her. The 

 image called up by his ecstatic words is that of those deep, soft 

 eyes \\ hich are a warm brown in some lights — for instance with 

 the light falling on them from one side only — and take a grey 

 tint when facing the light of the sky, and green tints at other 

 times, according to the lights that fall upon them ; and are there- 

 fore sometimes a puzzle to portrait painters. . Eyes, like the sea 

 and precious stones, catch lights and transmute them. The sea 

 is only green from the meeting of sunlight and blue sky light 

 in it. J. M. H. 



P.S. — Has it been remarked that the distinction between 

 yellow and blue tints — the only one made by the colour-blind, 

 according to Dr. Pole — is precisely the same as that made by the 

 sun in photography : all the warm tints (as an artist — who makes 

 the same distinction — would call those partaking of yellow) 

 coming out darker, and all the cold ones — or those partaking of 

 blue — lighter than in the object photographed ? 



Intellect in Brutes 



A CORRESPONDENT in NATURE, vol. xix. p. 268, describes 

 the actions of a water-rat which, he says, climbed up to a 

 window-sill, inconvenient of access, and thirteen feet from the 

 ground, in order to get some bread which was habitually put 

 there for the birds during the cold weather. As the rat had 

 never found food there bef re, the writer concludes that his 

 conduct cannot be attributed either to instinct or to experience, 

 but must be ascribed to a process of reasoning based on the 

 observati n of the flocking together of the birds, and the 

 inference that they must be attracted by food. Now it seems to 

 me that before we ascribe to a rat such complicated reasoning 

 powers it is necessary to ask if there is no other, simpler, way of 

 accounting for the phenomenon. I think there is. It is well 

 known that different species of animals vary greatly in the acute- 

 ness of their senses. To man, sight is the most important sense, 

 and the same is true of many other animals, and most birds. 

 The cat is a representative of another, smaller, class of animals, 

 whose most perfect organ of sense is the ear ; while the dog 

 lives in a world of sensations, the most important of which are 

 contributed by the sense of smell. To this last class bel ngs the 

 rat, which is noted for the acuteness of its scent. It is evident, 

 therefore, that the water-rat in question was led to the window- 

 sill by his nose, which, in his case, was a more trustworthy guide 

 than his eyes would have been. I do not wish to deny, by any 

 means, that animals have reasoning powers. On the contrary, I 

 am convinced that human and brute intellect differ only in degree, 

 not in kind; and I even adopt Haeckel's "cellular psychology," 

 W'hich attributes the elements of intellectual life — sensation and 

 volition — to infusoria and organic cells in general, in opposition 

 to the older "neural psychology," according to which psychic 

 activity begins with the nervous system in the scale of animal 

 life. But what we have to guard against is not to ascribe to 

 animals reasoning powers of a higher type than is consistent with 

 the development of their brain, especially when the actions 

 which seem to postulate such powers can be readily accounted 

 for by simply bearing in mind the extraordinary acuteness of one 



' Trans. Roy. SoJ., paper read June 20, 1872. 

 ' Trans. Roy. Soc. Kdin., vol. xiii. p. 370. 



or more of their senses. We are altogether too prone to judge 

 the mtellectual life of animals by the human standard, to imagine 

 that the eye is everywhere, as with us, the leading source of 

 knowledge ; and the neglect of the important r6le which the 

 sense of smeU plays in animal life has been particularly fruitful 

 of errors in philosophical speculation. It has, among other 

 things, helped to give a longer base of life to the old theory of 

 instmct, regarded as a mysterious power of nature. 



Berlin, February 8 Henry T. Finck 



Ear Affection 



The remarkable phenomenon described by your corre- 

 spondent "P," in Nature, vol. xix, p. 315, induces me to 

 bring to your notice that precisely the same effect was produced 

 in my own case a month ago, when partial deafness came on in 

 both my ears, whilst suffering from congestion of the mucous 

 membrane of the nasal passage and eustachian tube. Not being 

 aware that any prior case had occurred of a distinct difference of 

 a semitone, as indicated by the alternate application of a tuning- 

 fork to the two ears, I at once drew up a memorandum on the 

 subject, and handed it to Dr. Urban Pritchard, who was advising 

 me. Like your correspondent "P," I have also noticed the 

 double sound produced when I whistle, and more particularly 

 when I close both ears with my fingers. G. L, Wallich 



February 11 



Bees' Stings 



The American Quarta-ly Microscopical Journal, published 

 last October in New York, contains an elaborate article on 

 " The Sting of the Honey Bee," by J. D, Hyatt, Mr, Hyatt's 

 experience does not tally with that of your correspondent, R, A, 

 He says : "By allowing the bee to sting a soft piece of leather 

 an excellent opportunity is offered for studying the action and 

 mechanism, for the whole apparatus will ^be beautifully dis- 

 sected, the bee not appearing to be seriously injured by the loss. " I 

 should be happy to send the journal to R, A. if I knew his 

 address, W. Radford 



Sidmouth 



Electric Lighting V 



I notice in an article in Nature, vol. xix. p. 262, the fol- 

 lowing reference made to our electric light that it "does not 

 appear to give very great satisfation through its fluctuation." It 

 is true that at first we were caused some trouble owing to the 

 Serrin lamp not working properly, but having ; overcome the 

 difficulty we find it in our business, where it is necessary to show 

 colours correctly, a very great improvement on all our former 

 trials of lighting, and moreover, in its use we are not troubled 

 in our galleries and upper floors with the heat and fumes w'hich 

 with gas alight no amount of ventilation seemed to remove. 



It is not a pleasant light to read or write by owing to a certain 

 flicker which seems common to all the regulatoi's, but in ware- 

 house or show-room use this does not cause any inconvenience, 

 and we think in large places, especially those already having 

 motive power, that it must eventually supersede gas. § 



Regent Street H. J. NicoLL 



J?ELA TION OF METEORITES TO COMETS " 



II. 



n^HERE are two classes of shooting stars which have 



•*■ been sometimes spoken of as unlike, but which are 

 now admitted on all hands to be of common origin and cha- 

 racter, namely, those which come in quantities on certain 

 nights of the year, and give what is called a star shower, 

 and the sporadic meteors, such as we can see on any 

 clear night. 



In November, 1799, von Humboldt saw during his 

 travels in South America, a shower of shooting stars, and 

 he has given a glowing description of the sight. These 

 came on the morning of November 12. In 1832, 

 November 13, there Avas seen in Europe a display of 

 less brilliancy. It, however, attracted not a little atten- 



' A lecture delivered in the Mechanics' Course at the Sheffield Scientific 

 School of Yale College, U.S., by Prof. H, A. Newton. Continued from p. 

 317. ... 



