5IO 



NATURE 



[April 12, 1877 



at the last observation bad so closely approached the edge that it 

 was scarcely, if at all, visible, and the entire disc might then be 

 said to appear free from spots of any kind. On March 23 the 

 sun remained altogether clouded. At night, however, the sky 

 cleared, and I had a good view of the occultation of Kappa 

 Geminorum. The disappearance was, as usual, instantaneous, 

 but immediately after it a delicate ray seemed to shoot out from 

 the place of the star in a direction perpendicular to the edge of 

 the moon, and the appearance lasted about eight seconds. 

 Milbrook, Tuam, March 24 J. Birmingham 



a Centauri 



At the meeting of the Royal Astronomical Society December 

 8, 1876, Mr. Marth asked for measures of this binary. 



As the star never reaches more than li° above my horizon, 

 the definition must always be imperfect ; but the following 

 measures taken on the morning of February 22 appear consistent, 

 and may be useful until better results are obtained from the 

 southern hemisphere : — 



Epoch 1877 '14. Distance. Position. 



1 3'4 64-0 



2 3'i 64-5 



3 3"i 64-3 



4 37 647 



Mean ... 3*3 64 -4 



The component stars are of about the first and second magnitudes, 

 and their colour is yellow. Power employed, 240 ; definition 

 very bad. Maxwkll Hall 



Jamaica 



The Boomerang 



Will you allow me to add my experience of the use of this 

 weapon to that furnished by your other correspondents ? My 

 experience is mainly confined to the natives about the Conda- 

 mine and its affluents, where I was frequently in company with 

 natives for about a year. They had two weapons — one large, 

 for war, the other i-mall, for game. I should think the weapon 

 is seldom thrown in war, since most of their contests (such as 

 they are) take place in scrubb or forest, where it could not be 

 used to advantage ; but I have seen a native frightfully cut in 

 the abaomen, and was told by a native that he had been struck 

 by a boomerang thrown by the hostile party. I have seen a 

 few of these contests, but never saw the boomerang used in any 

 way. The "waddys" were thrown freely, the spear seldom. 

 The game boomerang is thrown among flights of ducks, and also 

 parrots when congregated on the trees and gathering nectar from 

 their flowers, and with marked effect. This I have seen several 

 times. There are two ways of throwing the weapon, which, as 

 I could throw it well at one time, I will endeavour to describe. 

 It is grasped quite at the end by the right hand and raised above 

 the htad, the elbow being bent, the weapon assuming a position 

 with its convex edge downwards on a nearly horizontal line at 

 right angles to the intended line of flight. The arm is brought 

 swiftly round from left to right, becoming gradually extended 

 until it reaches a line directly in front of the face, when the 

 weapon is delivered from the now straight arm, with the con- 

 cave edge towards the line of flight. This is the method of 

 throwing into the air. No dependence can be placed on the 

 return of the weapon within a circle of twenty yards, though it 

 sometimes returns dangerously near the thrower. If it meets 

 with an obstacle it is either stopped and falls dead to the earth, 

 or its course is changed. In either case its peculiar motion is 

 destroyed, as must be obvious. In the other method of throwing 

 the weapon is held in the same way, but delivered nearly on line 

 with the hip, and made to strike the earth about ten yards in front 

 of the thrower, pitching, I believe (though it is not easy to observe), 

 on one of its horns. Thence it ricochets and flies straight away 

 for perhaps seventy or eighty yards, keeping a position of about 

 four feet from the earth, and gradually rising until it is spent. It 

 returns very little if at all. In this way only can it be used for 

 war, since in the other it begins to mount at once, and would 

 soon be above the enemy's head. The weapon is made of various 

 woods, a piece with a slight elbow being selected. It is hardened 

 by baking. The right form is arrived at by trial, as I have seen 

 during the process of manufacture. Those sold to Europeans 

 are the failures. I had to pay a good price for the two I brought 

 home, but they were excellent specimens. 



The natives drive ducks. A flight is marked down on a small 

 creek ; men are then posted along the bank, others drive the 

 birds towards them, and the boomerangs are thrown as they 

 pass, I do not recollect having i-een the weapon used for ground 

 game. These are surrounded and killed with spears and 

 sticks. Arthur Nicols 



Is Meteorology a Science ? 



The recent article in Nature on the Treasury Blue Book 

 relating to meteorology brings into unpleasant prominence the 

 opinion of the eminent astronomer. Sir G. Airy, that meteoro- 

 logy is not a science ; and the evidence of the eminent physicist, 

 Sir William Thomson, to the same effect ; while a celebrated 

 philosopher in the columns of the Fortnightly Rei'iew has not 

 long since described meteorology as "a formless registry of 

 facts. " 



But surely these eminent authorities have hardly realised the 

 great change which has come over the whole aspect of meteoro- 

 logy since the introduction of synoptic charts ? 



Synoptic meteorology shows that the world is, broadly speak- 

 ing, covered with shifting cyclones and anti-cyclones, which have 

 each, subject to local, diurnal, and other variations, a charac- 

 teriitic weather, and physical appearance, and one great problem 

 of meteorology is to explain the observed weather over any area, 

 at any instant, by defining the position of these cyclones and 

 anti-cyclones. It is in fact analogous to that branch of geology 

 which explains the scenery and contours of any country by the 

 position of areas of upheaval, crumbling, and subsequent denu- 

 dation. 



But there is another problem for the meteorologist to solve, 

 viz., Given the position of the cyclones and anti-cyclones at any 

 instant, to determine their future course and changes ; and this 

 can even now be done in certain cases. As if the geolcgist^were 

 asked what the future course of the present state of the earth's 

 surface will be, where fresh upheavals or crumblings will occur, 

 and what the corresponding changes in scenery wiil be ? In 

 this case the position of the meteorologist is far in advance of 

 the geologist. 



But still another reproach is cast upon meteorology — that the 

 knowledge requisite to issue forecasts cannot be expressed in 

 mathematical formulae or in simple maxims. Here, too, the 

 analogy of geology may show that neither formulae nor maxims 

 are necessary to make a science. Just as a number of skilled 

 geologists, from long experience, agree as to the structure of a 

 complicated piece of country, so will a number of meteorolo- 

 gists agree as to the probable course of any series of cyclones 

 or anti- cyclones. 



The limits of a letter do not permit me to show why mean 

 values, or harmonic series can never much advance meteorology 

 as a science, if any better argument were needed than their 

 failure after a trial of forty years. 



But I think we are justified in saying that, since the introduc- 

 tion of synoptic methods, meteorology is as much a science as 

 geology ; that both are pure observational sciences, and that 

 their methods have much in common, while in some points 

 meteorology is even the further advanced of the two. 



21, Chapel Street, S.W. Ralph Abercrombv 



Atmospheric Currents 



I hope you will permit me to reply to Mr. Clement Ley's 

 letter on atmospheric currents in Nature, vol. xv. p, 450, 



It is certain that the earth's rotation cannot originate any 

 current, but modifies them when originated. 



We are agreed as to the cause of ihe trade-winds. The con- 

 troversy is as to the questions. Why the trade-winds do not 

 extend to the poles ? What is the cause of the counter-trades or 

 west winds between the trade-wind regions and the poles ? and 

 what is the cause of the polar depression of the barometer ? 



The polar depression of the barometer is due to the centri- 

 fugal force of the vortex which is constituted by the counter- 

 trades as they circulate round the pole from east to west. There 

 is a depression at the centre of every vortex, as any one may 

 see in a wash-basin. 



The counter-trades are " the reaction of the trade-winds," 

 The laws of motion make it impossible for the winds to have 

 any effect in either accelerating or retarding the earth's rota- 

 tion — supposing, what we are safe in taking as proved, that they 

 originate exclusively as the effect of solar heat. The effect of 

 the trade-winds alone, blowing from east to west, would be to 



