Aug. 17, 1888.] 



SCIENTIFIC NEWS. 



WHIRLWINDS AND WATER- 

 SPOUTS.— II. 



(Continued from p. 78 J 



'"THE whirlwinds which I observed on the ridges of our 

 high mountains (where the snow is generally agglo- 

 merated in a manner more or less compact) so that the 

 whirlwind can only raise up a sort of very dry rime, of 

 a very slight density, present, on a reduced scale (2 — 6 

 yards in height) the same form as the dust-whirlwinds 

 seen on dusty roads, i.e., that of an inverted cone. On 

 the contrary, the snow whirlwinds seen on the great table- 

 lands, where the snow is plentiful and powdery, exhibit 

 the aspects of the terrible sand-pillars of the deserts 

 (Fig. 3). Hence it seems to me that the density of the 

 materials lifted up modifies decidedly the general form 

 of the whirlwind, beginning even with its base of suction, 

 being acute in the one case and wide in the other. 

 Evidently the existence of conical whirlwinds raising up 

 snow and sand indicates a very considerable intensity. 



In conclusion, R. Duhnmel records his conclusions as 

 follows : — ■ 



Everything conspires to demonstrate that the whirl- 

 wind itself presents an ascending force, so that in its 

 whole mass the current sets from below upwards. 



In mountainous regions whirlwinds occur by prefer- 

 ence in certain places, rounded ridges, large open hills, 

 enclosed ravines (forming in a manner chimney-shafts), 

 high plateaus and points in valleys situated below currents 

 of air coming from passes which open above them. 



M. D. Colladon, of Geneva, forwards to La Nature 

 some further observations on the same subject : — 



" I have read with much interest M. H. Gilbert's note 

 on the whirlwind which he studied at Vincennes. The 

 most important matters are the formation of the point of 

 the whirlwind and the direction of the rotation, which is 

 that of the hands of a watch." 



In 1879 I noted down the following particulars on a 

 whirlwind which I watched for some minutes : — 



"On a fine day in July, and in very calm weather, 

 between 11 a.m. and noon, I was passing along the 

 Boulevard de la Coulouvreniere at Geneva, near a stony 

 place, where a great quantity of linen articles of different 

 sizes had been laid out in the sun to dry. All at once a 

 whirlwind with a perpendicular axis, and two or three 

 yards in diameter, rendered distinctly visible by the 

 rotation of a wave of dust, passed over this piece of ground 

 spread with linen, and turned a part of them over, 

 carrying them up at a dizzy speed above the roofs of the 

 town, where all these articles continued to whirl about 

 describing divergent cycles. Finally, at a height of 

 at least 600 to 700 yards these articles were scattered in 

 in different directions. This was evidently a whirlwind 

 with an ascending rotatory movement. The column 

 appeared, at the outset, to have the form of an inverted 

 cone. All the objects lifted up were drawn into the in- 

 terior, and then transported by the impulse of the air. 

 Such momentary whirlwinds sometimes occur in calm 

 and hot days in spring and summer, but they are visible 

 only if there are at their place of origin light bodies or 

 abundance of dust, and hence they often escape observa- 

 tion." 



If the whirlwind just described had not carried away 

 with it the linen, it would have ceased to be visible at 

 the height of thirty or forty yards. 



Whirlwinds in which the air ascends spirally have 

 been seen in various countries, in dusty plains, and 



generally in calm weather. Their form has been com- 

 pared by Humboldt to a funnel, the point of which rests 

 on the ground. In his " Pictures of Nature " he speaks 

 of whirlwinds of this kind observed in the Llanos of 

 Venezuela. 



Mr. Stephenson has observed similar phenomena in 

 the province of Behar on certain dusty plains near the 

 Ganges. He describes at the confluence of the Ganges 

 and the Sone two enormous dust columns of more than 

 four yards in diameter, the summit of which was lost in 

 the atmosphere. 



M. Adrien Arcelin, of Saint Sabin, sends to La Nature 

 a notice of a similar phenomenon recorded in 1873, near 

 Solutre. " A quire of so-called straw-paper which I used 

 for wrapping up objects collected in the excavations, and 

 which was lying on the ground at our feet, was whirled 

 into space. All the leaves parted company, and began to 

 rise turning over along helicoid trajectories which became 

 gradually larger. It was curious to see these twenty-four 

 sheets of paper whirling in the air like a flock of birds. 

 They went far beyond the summit of the rock which rises 

 90 yards above the place where we were standing, and 

 they lost themselves in the sky in the direction of 

 Vergisson. The whirlwind was, therefore, moving in a 



Fig. 3. 



north-westerly direction. The time was 4 p.m. The 

 weather was delightful, the sky clear, and the air calm 

 both before and after the event. 



Our party of ten labourers who were sitting on the 

 ground, eating, at the distance of about 20 yards, felt 

 nothing. There was no cloud of dust, as the ground was 

 overgrown with grass, and had it not been for the paper 

 the phenomenon would have quite escaped observation. 



Faye's Comet. — Faye's periodic comet was seen near 

 the calculated position by an observer at Nice Observatory 

 at twenty minutes after three on Friday morning. The 

 position was — right ascension 5I1. omin. 28sec. ; North 

 Polar distance 6gdeg. 59mm. i8sec. Comet Brooks was 

 in right ascension ioh. 2 2min., and North Polar 

 distance 4Sdeg. umin. at ten p.m. on the 9th inst., 

 and the daily motion was ji minutes decreasing right 

 ascension and 9 minutes increasing Polar distance. 



