430 



NA rURE 



{March 3, 1887 



identically the same. It produces either a temporary accelera- 

 tion, such as is due to alcohol, or else a remarkably steady 

 and high rate of growth. On the action of this reagent we 

 hope to make further observations. 



Qtiiiiiiie Chlori h. — Extremely dilute solutions acted poison- 

 ously, and produced a shortening of the tissues. When con- 

 traction took place it was manifested within a remarkably short 

 time. In one case contraction seemed to begin simultaneously 

 with the exposure to the poisou, and was certainly well marked 

 in less than one minute. 



Cmicliision. — The most interesting fact which we have esta- 

 blished is the possibility of stimulating turgescent tissue; to 

 increased elongation by such reagents as alcohol, ether, and 

 hydrocyanic acid. And we incline to think that our results 

 may help to direct attention to a factor in the problem of cell- 

 mechanism — namely, the protoplasmic element, rather than the 

 purely osmotic side of the question. 



SOCIETIES AND ACADEMIES 



London 



Royal Sociely, February 24. — "On the Relation between 



Tropical and Extra-Tropical Cyclones." By the Hon. Ralph 



Abercromby. Communicated by Mr. R. H. Scott, F.R.S. 



All cyclones have a tendency to assume an oval form ; the 

 longer diameter may lie in any direction, but has a decided ten- 

 dency to range itself nearly in a line with the direction of pro- 

 pagation. Tropical cyclones have less tendency to split into two, 

 or to develop secondaries than those in higher latitudes. A 

 typhoon which has come from the tropics can combine with a 

 cyclone that has been formed outside the tropics, and form a 

 single new, and perhaps more intense, depression. There is 

 much less difference in the temperature and humidity before and 

 after a tropical cyclone than in higher latitudes. The quality 

 of the heat in front is always distressing in every part of the 

 world. 



The wind rotates counter-clockwise round every cyclone in the 

 northern hemisphere, and everywhere as an ingoing spiral. 

 The amount of incurvature for the same quadrant may vary during 

 the course of the same cyclone ; but in most tropical hurricanes 

 the incurvature is least in front, and greatest in rear ; whereas 

 in England the greatest incurvature is usually found in the right 

 front. Some observers think that broadly speaking the incurva- 

 ture of the wind decreases as we recede from the equator. The 

 velocity of the wind always increases as we approach the centre 

 in a tropical cyclone ; whereas in higher latitudes the strongest 

 winds and steepest gradients are often some way from the centre. 

 In this peculiarity tropical cyclones approximate more to the type 

 of a tornado ; but the author does not think that a cyclone is 

 only a highly developed whirlwind, as there are no transitional 

 forms of rotating air. 



The general circulation of a cyclone, as shown by the motion 

 of the clouds, appears to be the same everywhere. All over the 

 world, unusual coloration of the sky at sunrise and sunset is 

 ■observed, not only before the barometer has begun to fall at any 

 place, but before the existence of any depression can be traced 

 in the neighbourhood. Cirrus appears all round the cloud area 

 of a tropical cyclone, instead of only round the front semicircle, as 

 in higher latitudes. The alignments of the stripes of cirrus appear 

 to be more radial from the centre in the tropics, than tangential, 

 as indicated by the researches of Ley and Hildebrandsson iri 

 England and Sweden respectively. Everywhere the rain of a 

 cyclone extends farther in front than in rear. Cyclone rain has 

 a specific character, quite different from that 'of showers or 

 thunderstorms ; and this character is more pronounced in tropical 

 than in extra-tropical cyclones. 



Squalls are one of the most characteristic features of a tropical 

 cyclone, where they surround the centre on all sides ; whereas in 

 Great Britain, squalls are almost exclusively formed along that 

 portion of the line of the trough which is south of the centre, and 

 in the right rear of the depression. As, however, we find that 

 the front of a British cyclone tends to form squalls when the 

 intensity is very great, the mference seems justifiable that this 

 feature of tropical hurricanes is simply due to their exceptional 

 intensity. 



A patch of blue sky, commonly known as the "bull's-eye," is 

 almost universal in the tropics, and apparently unknown in higher 

 latitudes. The author's researches show that in middle latitudes 

 the formation of a " buU's-eye " does not take place when the 



motion of translation is rapid ; but as this blue space is not 

 observed in British cyclones when they are moving slowly, it 

 would appear that a certain intensity of rotation is necessary to 

 develop this phenomenon. 



The trough j'henomena, — .such as a squall, a sudden shift of 

 wind, and change of cloud character and temperature, just as the 

 barometer turns to rise, even far from the centre — which are such 

 a prominent feature in British cyclones, — have not been even 

 noticed by many meteorologists in the tropics. The author, 

 however, shows that there are slight indications of these pheno- 

 mena everywhere ; and he has collatetl their existence and 

 intensity with the velocity of propagation of the whole mass of 

 the cyclone. 



Every cyclone has a double .symmetry. One set of phenomena, 

 such as the oval shape, the general rotation of the wind, the 

 cloud ring, rain area, and central blue space, are more or less 

 related to a central point. Another set, such as temperature, 

 liumidity, the general character of the clouds, certain shifts of 

 wind, and a particular line of squalls, are more or less related to 

 the front and rear < f the line of the trough of a cyclone. The 

 author's researches show that the first set are strongly marked 

 in the tropics, where the circulating energy of the air is great, 

 and the velocity of propagation snail ; while the second set are 

 most prominent in extra-tropical cyclones, where the rotational 

 energy is moderate, and the Iranslational velocity great. The 

 first set of characteiistics may conveniently be classed together 

 as the rotational, the second set as the translational, phenomena 

 of a cyclone. 



Tropical and extra-tropical cyclones are identical in general 

 character, but difler in certain details, due to latitude, sur- 

 rounding pressure, and to the relative intensity of rotation or 

 translation. 



Linnean Society, February 17. — Mr. W. Carruthers, F.R.S. , 

 President, in the chair. — The Uev. A. Johnson exhibited draw- 

 ings of an abnormal Begonia VciUhii grown by him the preceding 

 autumn. The peculiarity consisted in the flower having a single, 

 large, flask-shaped, ovarian-like organ (?) placed centrally, and 

 surmounted by a single, simple, straight style ; thu^ though 

 doubtless a male, indicating an hermaphroilite condition, while 

 presenting resemblances to the normal female organs of Launis 

 nobilis. — Mr. E. iM. Holmes exhibited some irregularly-developed 

 lemons, in which the carpels were more or less separated at the 

 apex ; the arrest of the normal union of the carpel being attri- 

 buted to the bite of ^'n insect in the early stage of the growth of 

 the fruit. — There were exhibited, for Mr. J. G. Otto Tepper, a 

 neviSlylidiiim (S. Tepperiana, F. Muell.), collected in November 

 1SS6 on Mount Taylor, Kangaroo Island, Victoria, Australia. 

 It was found in the interstices of a Tertiary limestone. Other 

 trees which grew in the neighbourhood were stunted Eucalypts, 

 Hawkeas, and an Acacia somewhat resembling W. pycnantha. — 

 Sir J. Lubbock drew attention to examples o{ Peziza coccinea from 

 Ilfracomhe. — A dried specimen of Pr-imula impcrialis, Jungh., 

 collected by Dr. Sydney Hickson in Java, was exhibited from 

 the Royal Gardens, Kew. This species is a giant form of 

 Primula, being over 3 feet in height. Phants of this Himalayan 

 and Malayan species are now under cultivation at Kew, and form 

 an interesting addition to this poptdar group of garden plants. — 

 Mr. G. Maw showed two rare Narcissi, both known under the 

 name of yV". ccrnuus. The daffodil discovered by Mr. Buxton in 

 the Pyrenees at 7000 feet altitude is interesting as the only white 

 form known in a wild habitat. A diminutive, orange-coloured 

 species, flowered by the Kev. C. Wolley Dod from _bulbs col- 

 lected by Dr. He iriqiies, of Coimbra, appears to be allied to 

 N. triatidrus. — Sir J. Lubbock read the second part of his paper 

 on phytobiological observations, and on the leaf of Liriodendron. 

 In CEnolhcva /lisOrla the seed-leaves are linear, terminating in 

 a large round expanion. There is nothing to account for it in 

 the seed, nor does it appear to be of any advantage to the young 

 plant. On watching the growth, however, and comparing it 

 with that of other allied species, the explanation appears to be 

 as follows : the cotyledons are at first round, but a growth takes 

 lilace at the base of the cotyledon, which closely resembles that of 

 the subsequent leaves, hence their peculiar figure in this species. 

 In allied species the seed-leaves consist of two parts, a terminal 

 portion — the true or original cotyledon — and a subsequent growth 

 resembling in each species their trae leaves. With reference to 

 seed-leaves in which the stalks are connate, <r.y. Smyrniunt, the 

 union ^eems clearly advant.ageous as giving additional strength. 

 Other characters in various species, i^/anlago, Tilia, Heliophila, 

 Cardaminc, &c. , were instanced. As to the tulip-tree (Lirio- 



