602 



NA TURE 



[October 21, 1897 



Messrs. Pound and Clements presented a communication on 

 the vegetation-regions of the Prairie Province. A portion of 

 the paper was devoted to a critique of the treatment accorded 

 by various authors to the floral covering of the North American 

 continent. The authors endeavoured to demonstrate the in- 

 tegrity of the Great Plains as a single vegetation province, and 

 summarised the most salient floral features. 



Mr. F. E. Clements also contributed a paper on the zonal 

 constitution and disposition of plant formations. 



On the species of Picea occurring in the North-Eastern 

 United States and Canada, by Prof. D. P. Penhallovv. Since 

 the time of Pursh, the validity of the red spruce as a distinct 

 species has been generally denied by systematic botanists. In 

 1887 Dr. George Lawson maintained that the red and black 

 spruces are distinct species. This view has been sustained 

 during the last year by Britton in his illustrated " Flora of 

 North America." Prof. Penhallow's studies have led him to 

 the conclusion that there are abundant reasons for the separation 

 of Ptcea rubra as a distinct species. Incidentally, attention was 

 directed to a form of the white spruce characterised by its 

 foetid odour, and its strongly glaucous, rigid and often cuspidate 

 le£n-es, which are commonly broadened at the base. The name 

 of fatida is suggested for this form. 



Paleobotany. 



Notes on fossil Equisetacere, by A. C. Seward. The author 

 of these notes gave examples of the difficulty of distinguishing 

 between certain Palaeozoic fossils referred to Equisetites and the 

 genus Calaviites. He expressed the opinion that the fused 

 leaf-segments usually regarded as characteristic of Equisetites 

 may not afford a .trustworthy distinguishing feature. Reference 

 was made to Equisetites Heiningwayi, Kidst, from the English 

 coal-measures as a species of which the precise affinity remains 

 doubtful. Evidence was brought forward that the Jurassic species 

 originally described by Bunbury as Calamites Beaitii, and 

 referred by some authors to the Monocotyledons, should be 

 referred to Equisetites. Another Jurassic species, Equisetites 

 lateralis, was also described, and reasons were given for regard- 

 ing this species as a true Equisetites rather than a form of 

 Phyllotheca or Schizoneura. 



On Monday afternoon, August 23, a lecture was delivered by 

 Mr. A. C. Seward, on fossil plants. The lecturer gave illustra- 

 tions of the bearing of Palseobotany on the problems of plant 

 evolution, and special reference was made to the genera Ginkgo, 

 Bennettites, Lyginodendro7i, and others. 



ON OBTAINING METEOROLOGICAL RECORDS 

 IN THE UPPER AIR B V MEANS OF KITES 

 AND BALLOONS} 



A KNOWLEDGE of the physical conditions which prevail up 

 -^ to the highest cloud levels, five to nine miles above the earth, 

 is of great importance to meteorologists, who until recently have 

 been studying principally the conditions existing near the floor 

 of the aerial ocean, and from that standpoint have endeavoured 

 to formulate the laws, which control the pressure, temperature, 

 humidity, and currents in the great volume of air above them. 

 Continued and systematic observations on mountains in different 

 parts of the world latterly have contributed much to our know- 

 ledge of the approximate conditions of the atmosphere, under 

 various circumstances, up to a height of more than three miles 



above sea- level ; but the mass and surface of the mountain, 

 even when this is an isolated peak, influence very considerably 

 the surrounding air. Recognising, then, the value of the de- 

 termination of the true conditions of the free air, let us consider 

 what methods are available for this investigation, which must 

 necessarily be sporadic and of shorter duration than if conducted 

 on mountains. In the writer's opinion, free balloons with 

 aeronauts cannot be recommended on account of the large cost 

 in money, and sometimes the loss of life, which attend their 

 frequent use, while without artificial aids to respiration the 

 aeronaut cannot rise much above five miles. Captive balloons, 

 with observers, have been used in England, and more recently, 

 with self-recording instruments, in Germany ; but their height is 

 limited to about two thousand feet by the weight of the lifted 

 cable, and a wind which is sufficient to overcome their buoyancy 

 drives them down and occasions violent shocks to the suspended 

 instruments. A kite-balloon on trial in the German army is 



1 By A. Lawrence Rotch. (Reprinted from the Proceedings of the 

 American Academy of Arts and Sciences, vol. xxxii. No. 13, May 1897.) 



NO 1460. VOL. 56] 



intended to combine the advantages of a kite and a balloon; but 

 the cost and the moderate height attainable render it inferior to 

 the simple kite for meteorological researches, except during 

 calms which sometimes occur at the earth's surface, but rarely 

 extend aloft. 



There remain kites and unmanned balloons, both recording 

 graphically and continuously the chief meteorological conditions, 

 and these it is my intention to describe in this paper. The 

 recent development of the kite for meteorological purposes has 

 taken place in the United States, while the use of the automatic 

 balloon for obtaining data at very great altitudes has hitherto 

 been confined to Europe. 



Kites appear to have been first applied in meteorology by 

 Alexander Wilson, of Glasgow, who in 1749 raised thermo- 

 meters attached to the kites into the clouds ( Trans. Roy. ' Soc. of 

 Edinbtirgh, vol. x. part ii. pp. 284-286). Three years later, 

 Franklin performed in Philadelphia his celebrated experiment 

 of collecting the electricity of the thunder-cloud by means of a 

 kite (Sparks's " Works of Benjamin Franklin," vol. v. p. 295). 

 Although kites have served a variety of purposes, their first 

 systematic use in meteorology was probably in England between 

 1883 and 1885, when E. D. Archibald made differential 

 measurements of wind velocity by anemometers raised by kites 

 fifteen hundred feet (Nature, vol. xxxi.). In 1885, A. McAdie 

 repeated Franklin's kite experiment on Blue Hill, using an 

 electrometer {Proceedings of the American Academy, vol. xxi. 

 pp. 129-134), and in 1891 and 1892 made simultaneous 

 measurements of electrical potential at the base of Blue Hill, 

 on the hill, and several hundred feet above it with kites as col- 

 lectors {Annals., Astr. Obs. Han). ColL, vol. xl. parts i. and ii.. 

 Appendices A and C). The invention of light-weight self-re- 

 cording instruments made it possible to obtain graphic records 

 in the air by means of kites, and after W. A. Eddy had intro- 

 duced tailless kites into America, and had attached a mini- 

 mum thermometer in 1891 {Am. Met. Jourtial, vol. viii. pp. 

 122-125), a thermograph reconstructed of lighter materials by 

 S. P. Fergusson, of the Blue Hill Observatory, was raised on 

 August 4, 1894, 1430 feet above the hill {ibid. vol. xi. pp. 

 297-303). It was no doubt the first instrument, recording con- 

 tinuously and graphically, to be lifted by kites, and it permitted 

 simultaneous observations to be obtained in the free air and near 

 the ground. This method of studying the meteorological con- 

 ditions of the free air has ever since been in regular use at the 

 Blue Hill Observatory ; but notwithstanding" the general interest 

 which has recently been aroused in kites, it is not known by the 

 writer that meteorographs have elsewhere been raised by them. 

 The details of the work, as now carried on at Blue Hill, are 

 as follows. The kites, which have no tails, are of Eddy's 

 Malay, or of Hargrave's cellular types, the former presenting a 

 convex surface to the wind, and the latter two pairs of superposed 

 planes, each pair being connected by side planes. In addition 

 to the two leading kites, others are attached by independent 

 cords to various points of the line, which is a steel music wire, 

 0"033 inch in diameter, having a tensile strength of three 

 hundred pounds, and weighing fifteen pounds per mile. The 

 meteorographs are composed mostly of aluminium and weigh 

 less than three pounds each, the one constructed by J. Richard, 

 of Paris, recording on a single clock cylinder atmospheric pres- 

 sure, air temperature, and relative humidity {La Nature, 

 8 Fevrier, 1896), while that made by Mr. Fergusson similarly 

 records wind velocity and air temperature. One of these instru- 

 ments is hung to the wire between two kites, in order to ensure 

 its safety in case of breakage of the wire or of one kite, or the 

 failure of the wind to support the latter. The wire is coiled 

 upon the drum of a windlass, which may be turned by two men, 

 and a measuring device registers the amount of wire uncoiled, 

 while the angular elevation of the meteorograph, when not 

 hidden by clouds, is observed from time to time with a surveyor's 

 transit at the windlass or at the ends of a base line. From these 

 data, or from the barometric record, the altitude of the meteoro- 

 graph is calculated. Kites may be flown in all kinds of weather, 

 whenever the wind's velocity is between fourteen and thirty-five 

 miles an hour : and since on Blue Hill the average velocity is 

 more than eighteen miles an hour, days are frequent when flights 

 are possible. 



Probably the greatest elevation yet attained by kites, and cer- 

 tainly the highest level to which kites have lifted a meteorograph, 

 is 8740 feet above Blue Hill. This was accomplished, October 

 8, 1896, by the aid of nine kites, having a total area of 170 

 square feet, which gave a maximum pull at the ground of 



