March 2, 191 1] 



NATURE 



but dangerous to the touch. It grows from 2 or 3 inches 

 10 10 or 15 feet in height, and emits a disagreeable odour, 

 ijays a traveller : ' Sometimes, while shooting turkeys in 

 the scrub, 1 have entirely forgotten the stinging tree till 

 I was warned of its close proxnnity by its smell, and have 

 often found myself in a full forest of them. 1 was only 

 once stung, and that very lightly. Its effects are curious. 

 It leaves no mark, but the pain is maddening, and for 

 months afterwards the part when touched is tender in 

 rainy weather, or when it gets wet in washing, &c. I 

 have seen a man who treats ordinary pain lightly rolling 

 on the ground in agony after being stung, and I have 

 known a horse so completely mad after getting into a grove 

 of the trees that he rushed open-mouthed at everyone who 

 approached him, and had to be shot. Dogs when stung 

 will rush about whining piteously, biting pieces from the 

 affected parts.'" Mr. N. E. Brown, of the Royal 

 Gardens, Kew, made an interesting contribution (Gard. 

 Chron., loc. cit., p. 567) of his personal experience con- 

 cerning the virulent effect of the sting of this species in 

 the palm-house at Kew. Tokutaro Ito. 



Tokio, January 25. 



The Sailing-Flight of Birds. 



Since Mr. F. \V. Headley urges (February 16, p. 511) 

 readers of Nature to make observations on the flight of 

 the albatross, possibly a few remarks may be of interest 

 from one who, as a student of aerodynamical problems, 

 has carefully watched such wonderful performances. 



One point which has always struck me is that the 

 albatross almost invariably flies in immense circles, ever 

 varying in size and direction. Sometimes the bird will be 

 high overhead, then, swooping down on a curve, will skim 

 closely over the tops of the waves, then suddenly rising 

 again will float away to perhaps half a mile off, gradually 

 sweeping arcund, and perhaps again attaining a consider- 

 able elevation. It seems quite impossible to decide, from 

 observation, whether the elevation is gained from uptend- 

 Ing winds. Without doubt, the bird takes every advantage 

 of each puff or eddy he can find, but he does not progress, 

 as in Mr. Mallock's figure, steadily from wave to wave, 

 rising and falling with the waves. Nor does he, so far 

 as one can judge, invariably rise when facing the wind, 

 and vice versa. That albatrosses, as well as other birds, 

 seem always to soar in circles, may be due to the circum- 

 stances that, for instance, in following a ship, they have 

 to circle round and round in order to keep near it, not 

 being able to fly at such a slow speed as that of the ship 

 (and therein is a hint to our cross-Channel aviators). So 

 too vultures and eagles may soar around, not wishing to 

 depart from the district which they are watching. But the 

 question to which I have long wished for a reply is, 

 "Can birds soar in a straight line?" I remember many 

 years ago seeing, on the Nile, flocks of pelicans gliding 

 along on outstretched wings. Now these birds were pro- 

 gressing up the river, performing actual journeys, but I 

 cannot remember whether they were actually soaring in a 

 straight line all the time. 



I have frequently noted, what is patent to all, that in 

 calms there is no true soaring ; also I feel sure that 

 there is no kind of motion of the wing such as Mr. Hearn 

 suggests. One thing is certain, and that is that a soar- 

 ing bird, especially the albatross, always progresses at 

 great speed. Having once obtained the initial impulse, 

 there is so very little head resistance offered to forward 

 motion by the bird that the speed slackens but little. He 

 progresses, as described by Lnntjley, in the manner of a 

 skater skimming over thin ice, travelling so fast that the 

 Ice has not time to break. 



Much of interest on this matter is to be found in the 

 old annual reports of the Aeronautical Society. In that 

 for the year 1868 there is an interesting discussion in 

 which Mr. Young is quoted as saying that he had noticed 

 '' the hollow form of birds' wings ; these were not planes ; 

 Indeed, a little consideration would show that the curved 

 surface is better than a true plane. . . . He concluded 

 that the best means of flight is by a curved wing." A 

 great deal has been said on this subject during the last 

 Jew years, but how many have read these old, and often 

 Instructive, discussions? B. Baden-Powell. 



NO. 2If^7, VOL. 861 



The Non-simultaneity and the generally Eastward 

 Progression of Sudden Magnetic Storms. 



Fact. 



It will be necessary, first, to my regret, to direct atten- 

 tion to some further errors in Dr. Krogness's communica- 

 tion in Nature, December 8, 19 10, p. 170, to which I 

 made reply in the issue of January 5, p. 306. He ques- 

 tioned the correctness of our time of beginning of the 

 disturbance, May 8, 1902, as recorded on the horizontal 

 intensity curve at Potsdam, viz. i2h. om. Greenwich mean 

 civil time, whereas his determination for the same station 

 was iih. 58m. In my reply, I stated {idem, p. 307) that 

 Dr. Krogness must have made an error somewhere, for, 

 upon repetition of our time scalings, based upon the data 

 supplied us by the Potsdam Observatory, we got our 

 identical result. I next wrote to the Potsdam Magnetic 

 Observatory and requested that the time be scaled with 

 all possible accuracy from the original magnetogram. 

 Under date Potsdam, January 20, 1911, Dr. Venske gives 

 the time in question as iih. 59-7m., hence within o-3m. of 

 our time, but differing 1.7m. from that of Dr. Krogness. 



Furthermore, in compliance with a circular request, I 

 am receiving almost daily from observatories over the 

 whole globe fresh data on the fifteen sudden disturbances, 

 July 29, 1906, to September 25, 1909, first investigated 

 by Mr. R. L. Faris for the five Coast and Geodetic Survey 

 observatories. It will be recalled that Mr. Faris's data 

 had furnished important testimony on the question as to 

 the strict simultaneity of abruptly-beginning disturbances. 

 Both Drs. Chree and Krogness have attempted to break 

 down this testimony, but the data received thus far from 

 other observatories are bearing out the conclusions 

 previously drawn. 



Table I. contains the time data for the very same dis- 



Table I. — Greenwich Mean Civil Times of beginning of 

 Disturbances in the United States and at Potsdam. 



turbances chosen by Dr. Krogness. Confining our atten- 

 tion to the horizontal intensity disturbance curves, just as 

 he does, we have first the mean time of beginning as 

 derived from the five Coast and Geodetic Survey observa- 

 tories (Faris's data, the means being formed by Dr. 

 Krogness ; for the last disturbance the record at Sitka was 

 missing, so that in the mean only four observatories are 

 embraced). Next is given the times of beginning for the 

 Potsdam Observatory, first as derived by Dr. Krogness 

 and employed in his communication {idem, p. 171), next 

 as recently scaled by Dr. Venske at Potsdam, using the 

 original magnetograms. Forming the differences P 

 (Potsdam), U (United States), it is seen that for the 

 Krogness scalings there are three plus differences, two 

 minus ones, and one zero, resulting in an algebraic mean 

 of but -I- 003m. The case is, however, different for the 

 next column, which depends upon the Venske, i.e. the 

 original data of the Potsdam Observatory ; there are now 

 five plus differences and but one minus, the algebraic mean 

 being -t-o-47m. or o-44m. higher than that of Dr. Krogness. 

 These differences (P-U) are small quantities, to be sure, 

 but the interesting point is that, in every instance, for the 

 Venske figures they are in the same direction as deter- 

 mined by me from the five Coast and Geodetic Survey 

 observatories alone, and as published in Terrestrial 



