592 



NATURE 



[April 23, 1896 



of this arrangement it is possible to make the rotating disc travel 

 horizontally above a large table in which are fixed a great number 

 of pins, to the head of each of which is attached a bit of wool 

 some centimetres in length, and thus forming many flags, which 

 will show us the directions of the wind in each point traversed 

 by the cyclone. In the centre of the table a hole is pierced 

 communicating underneath with a very sensitive barometer, 

 which will show us the variations of atmospheric pressure at the 

 passage of the meteor (Fig. 8). 



We set the rotating disc in rotation after having placed it 

 above one of the extremities of the table ; you see at once all 

 the flags situated underneath indicate the directions of the wind. 

 Those which form the centre of the whirlwind remain flat and 

 rest inert on the table, their extremities directed one towards 

 the other. They represent wonderfully well the central calm. 



The flags surrounding the central calm form a circumference ; 

 they imply a wind forcing them all in a direction slightly centri- 

 petal, and ascending. In the following ranges the pieces of 

 wool place themselves again along a circumference, but scarcely 

 showing the centripetal direction, and not at all the ascending 

 one ; then the more distant the flags are from the centre, the 

 more they inflect towards the table, and indicate the descending 

 wind ; at the exterior circuit the wool takes centrifugal direc- 

 tions ; it is air which escapes from all sides on the borders of 

 the cyclone. 



Now, if we make the artificial cyclone travel horizontally, by 

 moving the crane on its pivot, you will see that the central 

 calm shows itself every instant at a new place, which is very 

 easily observed by the aspect of the flags occupying the centre, 

 which fall down suddenly and rest inert on the table. On the other 

 hand the flags immediately adjacent raise themselves quickly, 

 caught up by the tempest, and those which but recently were 



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1, . '; "iiiil|l!i!,i!|ii!|lii!J]iIliiil,,Mr,. 



^Vf-fc^^K 





'^-x^d^- 



^.A. y\ y^: A 



\mf^>:^x. 



Fig. 8. — Artificial reproduction of cyclonic phenomena. 



pointing in one direction, turn all at once in the opposite one, 

 and make it possible to observe with all its sharpness the abrupt > 

 change of wind which takes place on leaving the central calm. | 



By making the cyclone travel with sufficient quickness, the 

 flags permit us to take note of the dangerous and manageable 

 sides of a cyclone, according as one looks at the semicircle in 

 which the wind turns in the same direction as the movement of 

 translation, or in the opposite one. 



The variations of pressure are indicated by the passage of the 

 cyclone above the hole made in the table, and communicating 

 with the barometer ; you see the needle falling little by little, 

 indicating the minimum precisely at the moment when the centre 

 of the cyclone passes above the hole, then rising slowly. 



A thermometer sufficiently sensitive, placed in the centre of 

 the cyclone, allows us to observe a rise of temperature. 



In great cyclones, a ship on reaching the centre not only 

 finds a general calm, but the sun or stars may be seen to shine 

 through a great opening in the clouds ; it is the eye of the storm. 



In order to explain this fact, it suffices to remark that a cyclone 

 is only in fact a water-spout of enormous diameter, in the im- 

 mense sheath of which rages the storm of a descending move- 

 ment, dragging down the hurricane and the clouds from the 

 high regions to the level of the sea ; but, as in the water-spout. 



the central nucleus remains free, and allows a clear sky to be 

 seen. 



The realisation of this eye of the storm succeeds equally well 

 with steam or smoke by taking necessary precautions with the 

 experiment. 



Finally, as the centre of the cyclone is free of water vapour 

 (at least in the visible form), whilst in the enveloping sheath 

 storm and darkness reign, is it not evident that a hygrometer 

 placed in this cloudy sheath will show a degree of moisture above 

 that of the central nucleus ? 



To sum up— it may be seen that, however small the scale of 

 the experiments in comparison to that which passes in nature, 

 nevertheless these experiments reproduce with fidelity and with 

 all the particularities of the great natural meteorological pheno- 

 menon. 



The experiments which you have just seen will, I hope, suffice to- 

 show you how complete the experimental syntheses are, and how 

 they represent the natural phenomena in the smallest details. 



I will conclude by making the simple remark that meteorolog> 

 gains in extent and certainly when we treat it as an experi- 

 mental science. A. CoRN'U. 



IMMUNISATION AGAINST SERPENTS' 

 VENOM, AND THE TREA TMENT OF SNAKE- 

 BITE WITH ANTIVENENE.^ 

 II. 



T^HE experiments now to be described were made with anti- 

 -*■ venene derived from a horse which had last received a dose of 

 cobra venom estimated to be twenty times the minimum-lethal. 

 On some previous occasions I have stated 

 the results of observations on the antidotal 

 value of the blood -serum of rabbits which 

 had last received thirty and fifty times the 

 minimum-lethal. The antivenene obtained 

 from cats and white rats has also been ex- 

 amined. The special interest, however, is 

 attached to antivenene derived from the 

 horse, that it is more likely than any others 

 to be used in the treatment of snake-bite 

 in man. 



The experiments were so planned as to 

 obtain in different conditions of administra- 

 tion as exact a definition as possible of the 

 antidotal power of the antivenene. In the 

 meantime, four series of experiments have 

 been undertaken on rabbits. In one series 

 the venom was mixed outside of the body 

 with the antivenene, and immediately 

 thereafter the mixture was injected under 

 the skin of the animal ; in the second 

 series the venom and antivenene were 

 almost simultaneously injected into oppo- 

 site sides of the body ; in the third series 

 the antivenene was injected some consider- 

 able time before the venom ; and in the fourth series the venom 

 was first injected, and thirty minutes afterwards the antivenene. 

 In the experiments of the first series, the doses of cobra 

 venom administered were the minimum-lethal, one-and-a-half 

 the minimum-lethal, twice, thrice, four times, five times, eight 

 times, and ten times the minimum-lethal. In the case of each 

 dose of venom, experiments were made with different quantities- 

 of antivenene, until the smallest quantity required to prevent 

 death was discovered. In order to render it certain, in this andl 

 in the other series, that a lethal dose had been administered in the 

 experiments with the so-called minimum-lethal, the minimum- 

 lethal indicated by previous experiments was not used, but 

 instead of it a slightly larger dose ('00025 instead of "00024 

 gramme per kilogramme). 



When this certainly lethal dose, capable of producing death 

 in five or six hours, was mixed with the antivenene, and the 

 mixture injected two minutes afterwards, under the skin, it was 

 found that so small quantities were sufficient to prevent death 

 as "ooi cc. . "oooS cc, '0005 cc, and '0004 cc. (i/iooo, 1/1500,. 

 1/2000, and 1/2500 of a cc. ) for each kilogramme of the weight 

 of animal; with "0003 cc. (1/3333) per kilogramme, however,. 



iiiill 



the animal died. 



NO. 1382, VOL. 53] 



The antivenene was therefore found to be so 



1 Continued from page-572. 



