Dec. 1 6, 1886] 



NA TURE 



151 



Fireball of December 4, 1886 



The fireball seen at Stonyhurst College, near Blackburn, on 

 December 4, gh. i6m., and described in Nature of December 9, 

 p. 133, was observed here as follows : — 



1S86, December 4, gh. 17m., meteor equal 9. Path from 

 184° + 52" to 195' + 47°, ratherswift. At the point 180' + 50^° 

 it left a short brilliant streak of about ^°, which remained visible 

 to the eye for li minute. The meteor gave a distinct flash in 

 the moonlight, and the streak was projected just where the 

 maxinumi outburst took place. 



I have made a preliminary comparison of the observations 

 recorded at the two places, from which it appears that the fire- 

 ball, when first seen at Bristol, was some 64 miles yenically over 

 a point of the earth's surface near Farndale, in Yorkshire. 

 Travelling to south west, it evolved an enduring light-streak 

 when 49 miles high, near Thirsk, and disappeared near Otley, 

 at an elevation of 28 miles. 



These values are derived chiefly from the Bristol observation, 

 but they are somewhat uncertain, because the meteor was at a 

 great distance from that city, and appeared close upon the 

 sensible horizon. According to the Stonyhurst path, the figures 

 are less, the streak being computed at a height of 42 miles near 

 Thirsk, .and the end point of the meteor, ne.ar Otley, is indi- 

 cated at only ly miles above the eartb. The observations are 

 extremely discordant in altitude. The exact place of the streak 

 is given by both observers, and if we adopt a mean height of 

 45 miles we cannot be far wrong. 



The apparent radiant-point derived from the two paths is at 

 137° -f 59^ Before seeing the Stonyhurst observation, I attri- 

 buted the fireball to a shower near ;3 Urs;e Majoris, at 162° 4- 58°, 

 from which I saw many swift streak-leaving meteors at the end 

 of November and beginning of December, both in 1SS5 and 

 1886. I have a strong suspicion the observed paths of the fire- 

 ball are slightly in error, both as to direction and length, and 

 that the radiant should be near S Urss. In this case the motion 

 would have been from near Guisborough to Harewood at heights 

 of about 68 and 27 miles, but this does not differ materially 

 from the cour^e previously assigned. 



In presence of the doubts as to the fireball's exact path in the 

 air, it is most desirable to hear of further observations, and 

 re-investigate it. W. F. Den.n'i.n'g 



Bristol, December 1 1 



THE DISPERSION OF PLANTS B Y BIRDS 



THE part taken by birds in the dispersion of plants 

 is one of great interest in view of the diffi- 

 culty of accoimting for the appearance of certain 

 species in remote islands, no less than in localities 

 nearer to each other, or divided by such barriers as 

 mountain-ranges or deep seas. This subject has, more 

 or less, engaged the attention of botanical travellers 

 from the time when Darwin published his classical 

 " Journal of Researches," nearly fifty years ago, down to 

 the publication of Mr. Hemsley's " Botany of the Chal- 

 leiigt-r Expedition,'' Part I., which was issued as lately as 

 last year. In the careful summary of plants probably 

 distributed by birds, loc. cit. pp. 44-49, it is mentioned 

 that seeds may be carried by birds in either of two 

 ways. First, by seeds, especially those provided with 

 barbs and hooks, attaching themselves to the feathers of 

 birds, and, in the case of aquatic or burrowing birds, 

 being embedded in mud and thus carried accidentally 

 outside : or, secondly, by seeds swallowed by frugivorous 

 birds being for a time lodged within, and dejected after- 

 wards in such a state as to be capable of germination. 

 My object now is not to treat generally of this subject, 

 but to place on record two remarkable and striking in- 

 stances where seeds carried and dispersed by birds have 

 come immediately under my own observation. The ex- 

 amples which I shall here describe will, I believe, show 

 clearly that birds are capable of acting as very effective 

 agents in the dispersal of plants, and that the results are 

 so apparent as to be placed beyond reasonable doubt. 



In cases where seeds of a light character are provided 

 with barbs or hooks, they are well adapted for attaching 



themselves to passing objects, and are most favourably 

 placed for dispersal by means of birds. The particular 

 plant with barbed seeds which I describe under this 

 category has not, I believe, been mentioned before ; but 

 it is deserving of notice, as it fully meets all the require- 

 ments incidental to this form of dispersal, and, moreover, 

 I have had, for some years, very favourable opportunities 

 of observing its behaviour. This plant is Uncinia jamaic- 

 ensis, Pers. (Cyperaceffi), which grows in damp places in 

 the mountains of Jamaica, at elevations of 5000 to 5ooo 

 feet. It is generally found overhanging small pools of 

 stagnant water or on banks of mountain rivulets. Its 

 slender tapering spikes, when ripe, literally bristle with 

 long exserted rachilla, each shaped something like a 

 shepherd's crook (hamate), but with the hooked part so 

 closely fitting and elastic, that, if drawn along the back of 

 the hand, it would grasp and draw out the truest hairs. 

 Now, such places as are affected by this Uncinia are also 

 the frequent resort of numerous birds that come there to 

 drink or bathe, or to seek coolness and shade. In the 

 case of migratory birds, and especially those that cover 

 long distances in their flight, the high lands are generally 

 those first touched. This is doubtless owing to the eleva- 

 tion at which they fly to escape surface-currents or local 

 objects. I have often noticed birds from the north (the 

 United States) on their way south, and again birds from 

 the south returning to the north in early spring, fre- 

 quen'ing the high lands of Jamaica, and resting there for 

 a time before continuing their journey. Some such birds 

 have been easily caught by hand, so exhausted were they 

 with their long flight. In two instances I have found 

 small migratory birds so completely entangled in the 

 hooks of the Uncinia {Gardener's Chronicle, iSSl, p. 780) 

 that they were unable to extricate themselves ; and, unless 

 set at liberty at the time, would probably have died in 

 that situation. In these instances the hooks of the 

 Uncinia overstepped their proper function ; for, obviously, 

 no benefit would arise to the plant froin the death of the 

 birds, but only in the removal of the seed to another 

 place. Larger birds, of course, would not be caught ; 

 but on the other hand, if they came within reach of the 

 Uncinia, they could hardly get away wdthout detaching a 

 large number of the fruits and transporting them wherever 

 they went. In the case of the Uncinia, there is present 

 nearly every condition necessary to secure a very com- 

 plete dispersion of its fruits. The plant, in the first place, 

 is possessed of light portable seeds easily carried about 

 from one locality to another ; in the second place, the seeds 

 are provided with highly specialised hooks which effec- 

 tually grasp anything that comes within their reach ; and 

 lastly, the plant affects just those places which are visited 

 by birds, and seldom fails to secure a sure and trusty 

 carrier. It follows, as a matter of course, that Uncinia 

 jamaiccnsis is found plentifully distributed in the track 

 of migratory birds, and is found in similar situations in 

 the mountains on the mainland in Central .\merica, 

 Venezuela, Ecuador, &c. 



So much for seeds with barbs and hooks. We now 

 come to the second class of seeds, namely, those which 

 are swallowed by frugivorous birds and dejected in a 

 state suitable for germination. The most striking ex- 

 ample I know of the dispersion of such seeds, and of the 

 results which immediately follow, are shown in connection 

 with the pimento industry of Jamaica, which, as shown 

 below, depends entirely for its existence on the offices of 

 frugivorous birds. The pimento of commerce is the dried 

 frutt of the pimento allspice, or Jamaica pepper-tree 

 {Pinicnta vu/i^aris). No other country supplies this 

 article (although the tree itself is widely distributed 

 both in the West Indies and on the mainland), and the 

 value of the exports of pimento from Jamaica have 

 reached (in 1S80) a total of 100,000/. This is probably the 

 largest spice industry in the world, and, to repeat what is 

 mentioned above, it is wholly dependent upon the action 



