490 



SCIENTIFIC NEWS. 



[May 25, 18 



each other. M. Faj'e declares that whirlpools in water- 

 courses travel. M. CoUadon does not believe that liquid 

 vortices have ever been seen in water-courses in their 

 middle or lower parts. We see only the upper part, 

 but in the same river side by side we often see whirl- 

 pools which seem to rise to the surface. 



Aerial vortices move only when they are in moving 

 air, because they are generally produced by the action 

 of two or three winds of different directions which meet 

 each other. 



M. CoUadon excepts the case of vortices which are 

 the result of very decided differences in the temperature 

 of the dust on the ground and of the atmosphere. Such 

 will be the case with the dust whirlwinds of Africa, 

 Mexico, and India. 



In June, 1887, M. H. Hildebrand forwarded to M. 

 CoUadon his interesting memoir on the upper movements 

 of the atmosphere. He appears to share the views of 

 the latter meteorologist, and extends them to tornadoes. 

 He says : " Above a barometric minimum the air moves 

 along the surface of the globe in a form spiral towards 

 the centre, in such a manner that in the northern hemi- 

 sphere the rotation around this centre takes place in the 

 opposite direction to that of the hands of a watch ; near 

 the centre it departs more and more from the axis of 

 rotation ; in the upper strata of the atmosphere the air 

 spreads itself out in a uniform layer above the regions 

 of the barometic maximum. M. Dechevrens, Director of 

 the Observatory' of Zi-ka-wey, near Shanghai, in China, 

 has studied the typhoon of 1879. The wind, he says, 

 blew towards the centre, which is incontestable. Hence 

 the centre was the seat, in the lower regions at least, of 

 an aspiration and of an ascending movement. Professor 

 Elias Loomis, of Yale College, in the United States, 

 published in 1887 a memoir in which he conceives of 

 alternating cyclones, some ascending and others descend- 

 ing. Professor CoUadon has published various observa- 

 tions tending to prove that there are ascending vortices. 

 The following case may be cited: In July, 1887, there 

 occurred one on the Boulevard de la Coulouvreniere, at 

 Geneva, near a place where there were exposed to the 

 sun a great quantity of linen articles of different sizes. 

 Suddenly a whirlwind with a vertical axis passed over 

 the surface covered with linen, which was carried up with 

 a prodigious ascending speed to the height of 600 to 700 

 metres. These articles were scattered and dispersed in 

 different directions. This was doubtless a whirlwind 

 with an ascending rotary motion. 



Boy's Radio-Micrometer. — This instrument indicates 

 differences of temperature of the one-millionth of a 

 degree (centigrade). A very thin rod of bismuth 

 and a similar rod of antimony are soldered toge- 

 ther at one end, and connected by a slip of copper at 

 the other. This circuit is suspended by a quartz thread 

 between the poles of a powerful electro-magnet. On an 

 irradiation of the soldered part there is set up a current 

 which, even if very slight, is deflected by the two strong 

 magnetic poles. The apparatus is so sensitive that it 

 indicates the irradiation thrown by a candle upon a 

 halfpenny at the distance of 200 yards. 



New Anemometer. — M. Wolf (Cotnptes Rendus) handed 

 in, on behalf of Father Dechoverens, the description of an 

 anemometer for showing any ascending current of air, 

 even if very slight. 



Natural Itiistorj). 



POISONOUS FISHES.— II. 

 The Sting Ray and the NqIu. 

 Equally mysterious are the poisonous properties of the 

 tail of the Sting Raj', which are vested in a long bony 

 spine situated near the base of that member, and armed 

 upon either edge with a series of sharp, cutting teeth, 

 well shown in our illustration which, as well as that of 

 the weever fish given in our last articles, has been copied, 

 by kind permission of Dr. F. Day, from his work on 

 " The Fishes of Great Britain and Ireland." The 

 tail itself is very long and flexible — almost like the 

 lash of a whip — and the method of attack adopted by 

 the fish is to coil the member in question tightly around 

 its foe, and then to lacerate its flesh with the formidable 

 spine, which is worked rapidly to and fro with consider- 

 able force. The wound thus caused is in itself suffi- 

 ciently severe, but is always complicated by symptoms 

 which cannot be caused by the laceration alone, and 

 which point with unmistakable emphasis to the fact 

 that poison of a highly virulent character has been intro- 

 duced. 



Mr. C. B. Brown, for instance, in his " Camp and 

 Canoe Life in British Guiana," gives a vivid description 

 of the sufferings endured by one of his followers, who 

 contrived to tread upon a sting ray while vi'ading across a 

 narrow stream. The spine passed into the instep of the 

 unfortunate man, producing a jagged wound which bled 

 freely ; and although a strong dose of ammonia was at 

 once administered, and the wound itself dressed with 

 laudanum, the sufferer was writhing upon the ground in 

 agony in less than a quarter of an hour, the pain 

 extending, not to the injured limb alone, but also to the 

 groin and to one armpit. A strange symptom was the icy 

 coldness of the leg itself, which was so extreme that the 

 wounded man repeatedly strove to thrust the limb 

 actually into the flames of a fire over which it was sup- 

 ported by a companion. And not for three hours did 

 the pain abate ; even then to return at intervals for 

 several days afterwards. 



No doubt such an injury to the foot as that described 

 would alone be productive of considerable suffering ; but 

 it would not be sufficient to account, in this particular 

 instance, for the extension of pain to the arm-pit and the 

 groin, for the coldness of the wounded limb, or for the 

 great rapidity with which these symptoms were induced. 

 That poison of no little potency was injected into the 

 circulation there would seem no doubt at all. The only 

 question is. Whence did that poison proceed ? 



And that question we cannot answer. The dissecting- 

 knife reveals to us little or nothing. No poison-secreting 

 glands can we trace, no venom of any sort or description 

 can we find. All we can discover is that which we 

 knew already, that the spine at the base of the tail is the 

 sole instrument employed, and that it does not appear to 

 be in any way adapted to the transmission of a poisonous 

 fluid into the wounds which it inflicts. 



Very possibly the weapon itself is its own poison, so 

 to speak, its mere contact with the lacerated flesh 

 bringing about the results described. Such would at 

 least appear from the fact that the bony spine of this 

 remarkable fish is in great request among certain Indian 

 tribes for the purpose of tipping their war arrows and 

 spears, its serrated edges rendering its withdrawal from. 



