226 



SCIENTIFIC NEWS. 



[Sept. 7, 1888. 



Speed of Carrier Pigeons. — According to La Nature, 

 four pigeons belonging to Count Karolyi, flew, in 1884, 

 from Paris to Buda-Pesth in seven hours. Their speed 

 must, therefore, have been nearly 185 kilometres per 

 hour, or nearly 115 miles. 



Formation of Vegetable Mould. — According to La 

 Nature, Dr. M. C. Keller, of the University of Zurich, 

 has recently published his researches on this subject, 

 conducted in Madagascar. He fully confirms the results 

 of Darwin. In Madagascar an earth-worm more than a 

 yard in length (Geophagus Darwini) plays the principal 

 part in the formation of soil. 



Localisation of the Cerebral Centre of Visual 

 Perception. — Mr. Alexandre Vitzon, in a communication 

 laid before the Academy of Sciences, concludes that, in 

 dogs at least, the integrity of sight is connected with the 

 integrity of the occipital lobes of the brain, the destruc- 

 tion of this part of the brain occasioning immediate, 

 complete and permanent blindness in both eyes. 



A Train Stopped by Locusts. — Cosmos figures and 

 describes a recent scene of this kind in Algeria. The 

 crushed insects formed an oily paste upon the rails, so 

 that the wheels turned round without advancing. An 

 account has reached us of a train in Australia being 

 obliged, in order to force its way through a marching 

 column of caterpillars, to go back for upwards of a mile, 

 and then return at the highest possible speed. 



Ravages or Ferocious Animals in India. — According 

 to the Quarterly Review, the number of human beings 

 killed by wild beasts in 1886 was 2,707 : by wild 

 elephants, 57 ; by tigers, 928; by leopards, 194; by 

 bears, 113; by wolves, 222; by hyaenas, 24; by other 

 animals (doubtless chiefly death-snakes), 1,169. The 

 number of wild animals destroyed was, elephants, 7 ; 

 tigers, 1,464; leopards, 4,051; bears, 1,668; wolves, 

 6,725 ; hyaenas, 1,650 ; other animals, 6,852. 



CORRESPONDENCE. 



The Editor does not hold himself responsible for opinions expressed 

 by his correspondents, nor can he take notice of anonymous ct m- 

 munications . All letters must be accompanied by the name and 

 address of the writer, not necessarily for publication, but as a 

 guarantee of good faith. 



EXPANSION OF INDIA-RUBBER. 



In the very interesting paper on " Mechanical Refrigera- 

 tion " (in Scientific News, August 3rd, p. 100) there is a 

 statement which, left unexplained, might lead the general 

 reader into a misunderstanding of the properties of india- 

 rubber. To the correct remark, " Most substances expand 

 when they are heated, and contract when they are cooled ; 

 and, conversely, when they are compressed their tempera- 

 ture rises, and it falls when they are allowed to expand," 

 the author appends this doubtful note : — " India-rubber is 

 an exception. If an elastic band be suddenly extended 

 while it is touching the lips, it will feel warm, and when it is 

 relaxed it will feel colder." Now, in the extension of the 

 elastic band, there is no expansion, and in the relaxation 

 there is no compression. There is merely a change of form. 

 The cubic contents of the material are the same in all the 

 cases. If you compress cork, heat is generated ; in this case 

 the compression diminishes the cubic contents of the cork. 

 It is quite different with india-rubber. This can be tested 

 practically. If a cylindrical metal tube be completely filled 

 with a piece of india-rubber, and both ends be tightly closed; 



if pressure be applied to make the cylinder change its 

 shape and become elliptical in section instead -of circular, 

 what is the result ? It is well known that with the circular 

 section the cylinder's contents are a maximum ; and any 

 change of form would therefore diminish the contents. But 

 with the india-rubber the pressure does not alter the shape 

 of the cyclinder ; strike it with a hammer, and the effect is, 

 as it were, on a piece 01 solid iron. Pressure does not, then, 

 compress india-rubber, it only produces a change of form. 

 It is different with cork. Fit cork into the circular cylinder 

 and close the ends. Put on a pressure, and the form of the 

 cylinder is easily changed, because the cork is compressible, 

 with the additional exceptional property of elasticity which 

 enables it to recover its shape when the pressure is removed. 



J. G. M. 



A COBRA'S REVENGE. 

 In your issue of the 24th ult. was a cutting sent by G. G., 

 bearing this title, so thinking the subject of some interest, I 

 send you the enclosed cuttings from the Madras Mail :— 



" Sir, — Under the above heading there appeared in your 

 issue of 7th inst. an account of the death of engine-driver A 

 Fischer, atPennar, an employe in the Madras Railway Co's ser- 

 vice. The author of the account must have drawn deeply on his 

 imagination to concoct so tragic a tale out of the meagre facts at 

 his disposal. About 5 a.m. on the 3rd inst., while asleep in his 

 quarters, Mr. Fischer was bitten on the hand, by a rat as he 

 supposed at the time. At 6 a.m. he went to work, but feel- 

 ing unwell, obtained leave from duty at 7.30, and reported 

 himself to the apothecary. The symptoms, as described to 

 me, might have been caused by a cobra's bite, and in spite of 

 treatment, he rapidly got worse, and died at 2.45 p.m. No 

 one had seen a cobra in the compound for a month previous 

 to the occurrence, but a snake was killed in a tree in Fischer's 

 compound the day after his death, and shown to me on the 

 5th inst. It was not a cobra. There is no evidence to prove 

 that driver Fischer died from the effects of snake-bite, and it 

 is to be regretted that an autopsy was not held upon the 

 body. Unfortunately, I did not appear upon the scene until 

 after the funeral. — H. Leslie Anslcd {Medical Officer, Madras 

 Railway Co.)." 



" Sir, — The account in the Madras Mail of the 7th inst. of 

 the death of Mr. Andrew Fischer, of the Madras Railway Co., 

 at the Pennar Bridge Works, from cobra-bite, with the remarks 

 of ' Kellayan,' reminds me of a story which I have heard 

 repeated oftener than once by Major George Proudfoot, late 

 military secretary to H.H. the Nizam. When he lived at 

 Bowen Pillay, part of the cantonment of Secunderabad, 

 where the native cavalry regiment is quartered, he saw, one 

 evening as he went in his gate, a cobra hastening across the 

 large grassy compound towards a hedge. He gave it chase, 

 and seeing that he would not be able to overtake it before it 

 reached the hedge, he flung at it the heavy walking-stick he 

 carried in his hand, but missed it. Immediately the cobra 

 turned round, and when the Major made off in the direction of 

 his house it pursued him. The affair might have had a 

 tragic ending for him if his syces had not observed it from 

 the stables, and come to his rescue with bamboos, torn from 

 the stables' verandah, with which they despatched the cobra. 

 On the theory of the superior wisdom of the serpent, one 

 wonders why the cobra, when it knew that its pursuer had 

 parted with his weapon of offence, did not carry out its 

 original intention and quietly take refuge in its hole in the 

 hedge. On the theory of the revengeful nature of the cobra, 

 as stated by ' Kellayan,' the action of this particular member 

 of the species in following after its pursuer with deadly 

 intent is explained. — J." M. H. L. 



STRANGE ACTION OF A BEETLE. 



Referring to the curious behaviour of a beetle (Scientific 

 News, Aug. 17th), it occurs to me that the insect may have 

 been injured in one eye, and that, seeing only with the other, 

 it may have thought it was progressing in a straight line, 

 when in reality it was describing a circle. 



Althorne, West Bournemouth. C. Carus-Wilson. 



