38 



KNOWLEDGE & SCIENTIFIC NEWS. 



[Feb., 1905. 



remarkable effects on the indigenous vegetation'brought about 

 by their introduction. When Cook and Vancouver visited 

 New Zealand the constituents of the fauna and flora were, 

 Professor Kirk observed, very probablj' in much the same 

 condition as they had been in for many previous centuries. 

 Altered conditions following the immigration of white people, 

 the felling of forests, agricultural operations, and the introduc- 

 tion of various animals, many of which proved particularly 

 destructive to vegetation, rapidly made a marked impression 

 on the native flora. The clearing of the ground often meant 

 the practical extermination of indigenous species, while it 

 favoured the growth of aliens, seeds of which bad been intro- 

 duced in various ways, often mixed with agricultural seeds, in 

 ballast, or by means of animals. That the stronger-growing 

 species among the newcomers should spread and crush out of 

 existence the weaker native plants is not remarkable, but we 

 are told that the small slender-growing European grasses and 

 clovers have in places succeeded in displacing such stout 

 plants as Pliorm'uim tenax, the New Zealand Flax, and Cvpcnis 

 ustiiliitiis, a robust sedge. Rabbits and sheep have proved 

 disastrous to many species, especially those with very local dis- 

 tribution. Epilobiiim hnvifes, when Professor Kirk wrote, was 

 restricted to two localities, and could easily at any time have 

 been exterminated by a hungry rabbit or sheep. Cliniithiis 

 piniici'iis, a handsome leguminous plant, is now confined to one 

 or two small islands, where it owes its preservation to the 

 absence of sheep. Both writers have noticed that many of 

 the naturalised plants, after a period of remarkable vitality 

 and vigour, diminish in strength and numbers and sometimes 

 disappear altogether. 



An account of a botanical excursion to the Southern Islands 

 of New Zealand is given by Dr. Cockayne. These islands 

 include the Auckland group, Campbell Island, the .Antipodes 

 and Bounty Islands. The visit was made during midwinter, 

 which enabled the author to note some previously unrecorded 

 features of the vegetation. In Auckland Island, at about 

 50^' 45' south latitude, a single specimen of a common New 

 Zealand tree-fern (Himitilhi Smilhii) was found. This is a 

 particularly Interesting discovery, for it considerably extends the 

 southern range of these plants. Hitherto the known hmit for 

 tree-ferns was about 47 south latitude, where, at Port Otway, 

 in Patagonia, A IsaphHapruiiuita has been met with. Both these 

 species may be seen in some of our botanic gardens. An 

 enumeration of the species native of the islands, with a full 

 bibliography, concludes a most valuable treatise on insular 

 floras. 



* * * 



SupraL-terrestrial Vegetation. 



An article is contril>uted by M. \'irgile Brandicnurt to the 

 Ke.vur. Scientifiqiie on " supra-terreslrial " vetjct.-ilion, plants 

 which grow, not on the surface of the earth, but on w.iUs, 

 ;tnd roofs, and trees. They form an interesting study. 

 The oldest of them are those that grow on stone and brick 

 walls. Sixty-seven per cent, of these are plants with I'ne 

 seeds (saxifrage, arenaira, urtica. &c.), 13 per cent, plants 

 with winged seeds, that are easily dispersed by the wind, 

 9 per cent, plants with fleshy fruits, 6 per cent, plants with 

 hooked seeds, and 5 per cent, plants with an explosive 

 mechanism for dispersing the seeds. The plants of thatched 

 roofs are also numerous. Some of the older thatched 

 roofs have from 15 to 16 species of plants, and the general 

 average is eight. There is a special flora characteristic of 

 the tops of pollard willows. As many as S6 species have 

 been catalogued which grew thus. The most curious 

 instance of a parasitic tree was communicated by Dr. 

 Magnin. A mulberry tree took root on an ash, and usurped 

 its place by pushing the ash's* trunk down little by little till 

 it was lost to sight. 



METEOROLOGICAL. 



Meteorological Figures. 



.\n attempt is made by Dr. Kiippen, in the German 

 meteorological review Das IVrflcr, to express a mathemati- 

 cal relation between the intensity of heavy rainfall and the 

 time which it lasts. Me makes out a constant " n " for the 



relation, " n " being equal to the square root of the time 

 multiplied by the intensity. By a curious coincidence the 

 French meteorological review, Le Temps qu'il Fait, has an 

 article on recorded great falls of rain, or, perhaps, we should 

 say great " cloudbursts." On August 20, 1900, 30 mm., 

 or well over an inch of rain, fell at Maredsous 

 in ten minutes. The greater rate of fall recorded was, 

 however, at Turnhout on July 10, 1899, when 25 mm., or 

 nearly an inch, fell in six minutes, wliioh gives a rate of 

 4.2 millimetres a minute. In these heavy rainfalls the 

 distribution is very erratic. Thus, on .\ugust 27, 1902, 

 during a storm which swept Paris, 50 mm., or not far from 

 two inches, fell at the Pare des Buttes, Chaimiont, and less 

 than a auarler of an inch at Mont .Souris. 



The Velocity of the Wind. 



At the Eiffel Tower, during a storm on the night of the Tith- 

 12th of September, igoj, a rate of 42 metres a second (94 

 miles per hour) was recorded, but this record was eclipsed in 

 1S94, when on the 12th of November the wind attained a velocity 

 of 4S metres per second. America, however, cannot be beaten 

 in such matters. On the i8th of May, 1902, a storm vi-^^ited the 

 Pacific Coast, and near San Francisco the wind was measured 

 as travelling during several minutes at a speed of 53-6 metres a 

 second. Since the velocity undoubtedly as a rule increases 

 with altitude, it is not surprising to find that on the summits 

 of high mountains still greater speeds have been recorded. 

 M. Brunhes, the Director of the Observatory on the Puy de 

 Dome, claims the record wind velocity, for on the gth of 

 December, 1901, between 10.20 and 10.30 it blew at a mean 

 rate of no less than 70 metres a second, or 156 miles 

 an hour. 



» « » 



London Fogs. 



The report of the Meteorological Council upon "an Inquiry 

 into the Occurrence and Distribution of Fogs in the London 

 Area, during the Winters of 1901-2 and 1902-3 " has just been 

 issued. It is, of course, past our understanding why such a 

 report .should take nearly a year to compile, but we must rest 

 satisfied that such tardiness is not unusual with similar reports, 

 and that doubtless there was good reason for it. During the 

 last winter observations of the fog were recorded at 46 stations, 

 and thermometers were supplied to thirty fire brigade stations, 

 in order to determine the variations of temperature prevailing. 

 Among the various supposed causes of fog, radiation from the 

 earth's surface diuing calm nights is found to account for the 

 m.ajority. Warm air passing over previously cooled surface 

 causes many others, while " cloud fogs " form a third class. 

 There is no evidence to show that, in London, geological for- 

 mation affects the formation of fogs, and while fogs on the river 

 and in the open parks were frequent, it has not been found 

 that the neighbouring districts were specially infected. 



As rrgards forecasting the presence of fog, it is pointed out 

 how much more valuable night observation and early morning 

 reports would be than the present system of issuing the fore- 

 cast at 6 p.m. 



OR.NITHOLOGICAL, 



By W. P. PvcRAFT, A.L.S., !• ./...S., M.B.O.U., &c. 

 Flanningoes on the Medwa.y. 



Thk l-'irlil. Dec. 24, r(|)orts the occiurcnce of flamingoes 

 — presumably I'lucnicoplcrus rosfiis — on the Medway. A young 

 male " was recently shot on the marshes close to Gillingham," 

 and mistaken by the shooter for some kind of goose! It is 

 reported that another has been seen. 



Although there can be no doubt that some of the re- 

 corded occurrences of this species should be cancelled as 

 escaped birds, at least three previous instances of wild birds 

 taken in this country must be allowed to stand. Nevertheless, 

 so good an authority as Mr. J. E. Harting refuses to admit the 

 Flamingo to the list of British Birds. 



