224 



NATURE 



{July 4, 1889 



suspending wire-fibre. The drop to zero is simultaneous with 

 each flash of lightning. So certain is this relation that we 

 can time the lightning flashes without seeing them. After the 

 flash the needle begins to again move in one direction, repeating 

 its previous behaviour, so that our electrometer measurements 

 seem to prove that every flash of lightning relieves the state of 

 stress of the air, which we may compare with the glass in a 

 Leyden jar, the cloud and ground being the respective coatings. 



We may also get at the same result by noticing the effects of 

 the electrification of the dust, smoke, water, and other matter 

 in the air. Whenever our "collector" was "grounded," the 

 fine stream of water issuing from it preserved a certain even 

 rounded form, breaking into drops some four inches away from 

 the place of exit. Removing the " ground " connection, and the 

 stream being now under the influence of the thunder-clouds, the 

 steadily increasing electrification shows itself in the stream's 

 twisting and splitting into innumerable threads and spray ; but 

 with each flash of lightning the distortion instantly ceases, and 

 the stream has its normal character, only to be again distorted. 



For the benefit of those wishing to photograph lightning I 

 suggest this as a cheap and easy mode of getting warning when 

 to expose. A small tin case with ajnozzle giving a fine thread of 

 water or any form of the "burning match" device, well in- 

 sulated from the ground, and at some elevation, will indicate by 

 changes in the character of the stream or smoke, the approximate 

 degree of the electrification of the air. 



New York, U.S.A., June 20. Alexander McAdie. 



Upper Wind Currents over the Equator in the Atlantic 

 Ocean. 



Referring to the remarks of the Hon. Ralph Abercromby 

 on the above in Nature of May 30 (p. loi), I would ask for 

 the longitude and latitude for the two crossings of the doldrums, 

 to enable one properly to follow, and eventually work out, the 

 facts. For if our famous meteorologist, on the outer journey, 

 passed within one hundred miles of the West Coast of Africa, 

 the great chain of desert lands, extending many hundreds of miles 

 through Asia to the Sahara in the main weather thoroughfare, 

 would, by its influence, very much contract the width of the calm 

 belt, and otherwise draw the doldrum much north of the line to 

 what would be found more to the westward, where, as it neared 

 the American coast, the breadth of the doldrum belt would very 

 greatly increase ; so that, unless the doldrum was crossed at the 

 same longitude, the varying atmospheric conditions should not 

 be put down solely to the sun, or difference of December and May 

 seasons. 



Perhaps it is from want of the longitude that I am unable to 

 understand "how low clouds from the south-east drove over 

 north-east trades up to 15° north." All else is exceedingly 

 satisfactory with the law of winds, on the supposition that the 

 return crossing of the doldrum belt took place some hundreds 

 of miles further west, and about half that distance farther south, 

 than on the out journey. 



If I may be allowed to digress a little, I would refer to the 

 splendid travels by your correspondent, as published last Christ- 

 mas under the title of " Seas and Skies in many Latitudes," 

 which in some respects, I think, may be compared with the 

 celebrated Challenger Expedition. But, singularly enough, 

 while I am able to follow and accept all the author's research 

 and information, I find myself diametrically opposed to his con- 

 clusions. Thus, to quote from p. 428, we have : " Hence we see 

 the proof of the assertion that the trades and monsoons do not meet 

 and force one another to rise, and flow back poleward, but 

 that the two winds coalesce and form one great eastern current 

 over the doldrum." To my mental capacity all the proof is the 

 other way about. If the trades of both hemispheres do not 

 ascend over the calm belt, what other escape or vent is there for 

 them? I am aware that the Meteorological Section of the 

 Krakatab Committee of the Royal Society also favour the idea 

 of a great easterly current ever going west at a certain altitude 

 over the doldrums, but so far as I can find out they do not tell 

 us whence it cometh nor whither or how it goeth. In its circuit 

 going west, we naturally look for its return from the east, and 

 with the constant arrival of fresh winds vid the trades of both 

 hemispheres, it must accumulate if it does not flow back pole- 

 ward quite as fast as it arrivts, for we cannot entertain annihila- 

 tion of atmosphere any more than of matter. If some other 

 way of escape could be found, we should still have to face the 

 question, Whence comes the supply to the "trades if not from 



the poles, and whence our prevailing south-westerly winds if not 

 from over the doldrum.s " ? E. Foulger. 



Liverpool, June 18. 



P.S. — I do not call in question "the great easterly current 

 over the doldrum," but rather consider its discovery as extremely 

 interesting, it being just what a small school of meteorologists 

 would expect ; and it now appears to be left for them to 

 supply a theory for the cause of the direction and also of the 

 motive power of such an atmospheric passage, and possibly for 

 that of the Krakata~o dust. E. F. 



Patches of Prismatic Light. 



I AM curious to know if any of your readers observed the 

 following phenomenon in the sky, and could give any informa- 

 tion as to its nature. 



When driving with two friends on Saturday evening, June 22, 

 between 6.30 and 7 p.m., in the neighbourhood of Glatton, near 

 Peterborough, we observed on either side of the sun (the sky 

 being almost cloudless) two patches of prismatic light ; they 

 appeared to be of nearly the same size as the apparent disk of 

 the sun, and distant from it a hand's span measured from little 

 finger to thumb at arm's length. At the time there were a few 

 light clouds about, but the prismatic patches were not projected 

 on them, as the clouds passed occasionally in front of them, the 

 patches meanwhile shining through the thinnest parts, and 

 reappearing when the clouds had passed, clearly standing out 

 against the sky. There was no appearance of a continuous arch, 

 as in a rainbow, and, unlike a rainbow, the patches were on the 

 same side of the sky as the sun. I may add that the phenomenon 

 was seen by all three of us, and for half an hour after we first 

 noticed it. C. S. Scott. 



Glatton Hall, Peterborough, June 28. 



A Chimpanzee's Humour. 



In a recent lecture Mr. Romanes is reported as having strongly 

 denied the existence of even a trace of any feeling of the 

 ludicrous in the renowned chimpanzee "Sally." It may be 

 worth while to record a small fact observed by me lately, 

 tending, I think, to favour an opposite view. 



Being alone with a friend in Sally's house, we tried to get her 

 to obey the commands usually given by the keeper. The 

 animal came to the bars of the cage to look at us, and, adopting 

 the keeper's usual formula, I said, " Give me two straws, Sally." 

 At first she appeared to take no notice, although she had been 

 eyeing us rather eagerly before. I repeated the request with no 

 further result ; but on a second or third repetition she suddenly 

 took up a large bundle of straw from the floor and thrust it 

 through the bars at us, and then sat down with her back to us. 

 Our request was perhaps unreasonable, seeing that we had no 

 choice morsels of banana with which to reward her. She did 

 not, however, seem ill-tempered at our presumption, and the 

 next instant was as lively as ever. It seems to me that her 

 action on this occasion certainly came very near to an expression 

 of humour. Rather sarcastic humour perhaps it was, but she 

 certainly appeared to take pleasure in the spectacle of spmething 

 incongruous, and this surely lies at the base of all sense of the 

 ludicrous. Harold Picton. 



July I. 



PROF. HUXLEY AND M. PASTEUR ON 

 HYDROPHOBIA. 



ON Monday afternoon the meeting called by the 

 Lord Mayor to hear statements from men of 

 science with regard to the recent increase of rabies in 

 this country, and the efficiency of the treatment discovered 

 by M. Pasteur for the prevention of hydrophobia, was 

 held at the Mansion House. Much excellent work was 

 done. Several letters were read from those who were 

 unable to attend. Among these letters was the following 

 from Prof. Huxley : — 



'■'■Monte Geiieraso, Switzerland, June 25, 1889. 

 " My Lord Mayor, — I greatly regret my inability to 

 be present at the meeting which is to be held, under your 



