6o4 



NATURE 



[October i6, 1890 



terrestrial magnetism would be derived from a new magnetic 

 survey of the southern hemisphere extending from the parallel 

 of 40" S. as far towards the geographical pole as possible." 



Intimately connected with terrestrial magnetism are the phe- 

 nomena of auroras. Their nature is very obscure, but quite 

 recently a distinct advance has been made towards discovering 

 some of the laws which regulate them. Thanks to the labours 

 of Dr. Sophus Tromholt, who has spent a year within the 

 Arctic circle studying them, we now know that their movements 

 are not as eccentric as they have hitherto appeared to be. He 

 tells us that the Aurora Borealis, with its crown of many lights, 

 encircles the Pole obliquely, and that it has its lower edge sus- 

 pended above the earth at a height of from 50 to 100 miles, the 

 mean of 18 trigonometrical measurements, taken with a base 

 line of 50 miles, being 75 miles. The aurora forms a ring 

 round the Pole which changes its latitude four times a year. 

 At the equinoxes it attains lis greatest distance from the Pole, 

 and at midsummer and midwinter it approaches it most 

 closely, and it has a zone of maximum intensity which is placed 

 obliquely between the parallels of 60° and 70° N. The length 

 of its meridional excursion varies from year to year, decreasing 

 and increasing through tolerably regular periods, and reaching a 

 maximum about every eleven years, when, also, its appearance 

 simultaneously attains to its greatest brilliancy. Again, it has 

 its regular yearly and daily movements or periods. At the 

 winter solstice it reaches its maximum annual intensity, and it 

 has its daily maximum at from 8 p.m. and 2 a.m., according to 

 the latitude. Thus at Prague, in lat, 50° N., the lights appear 

 at about 8.45 p.m. ; at Upsala, lat. 60° N., at 9.30 p.m. ; at 

 Bossekop, 70° N., at 1.30 a.m. Now, while these data may be 

 true for the northern hemisphere, it remains to be proved how 

 far they apply to the southern. Indeed, seeing that the atmo- 

 sphere of the latter region is moister and shallower than that of 

 the former, it is probable that the phenomena would be modified. 

 A systematic observation of the Aurora Australis at a number 

 of stations in high latitudes is therefore desirable. 



Whether or not there is any connection between auroral 

 exhibitions and the weather is a disputed point. Tromholt 

 believes that such a relationship is probable ("Under the Rays," 

 1283). He says that, "however clear the sky, it always became 

 overcast immediately after a vivid exhibition, and it generally 

 cleared again as quickly" ("Under the Rays," 1235). Payer 

 declares that brilliant auroras were generally succeeded by bad 

 weather (" Voyage of Tegelhoff," 1324), but that those which 

 had a low altitude and little mobility appeared to precede calms. 

 Ross remarks of a particular display "that it was followed by a 

 fall of snow, as usual " (" Ross's Voyage," 1312). Scoresby ap- 

 pears to have formed the opinion that there is a relationship 

 indicated by his experience. It is, therefore, allowable to regard 

 the ultimate establishment of some connection between these two 

 phenomena as a possible contingency. If, then, we look at the 

 eleven-year cycle of auroral intensity from the meteorological 

 point of view, it assumes a new interest, for these periods may 

 coincide with the cycles of wet and dry seasons, which some 

 meteorologists have deduced from the records of our Australian 

 climate, and the culmination of the one might be related to some 

 equivalent change in the other. For if a solitary auroral display 

 be followed by a lowered sky, surely a period of continuous 

 auroras might give rise to a period of continuous cloudy weather, 

 with rain and snow. Fritz considers that he has established 

 this eleven-year cy;le upon the strength of auroral records ex- 

 tending from 1583 to 1874, and his deductions have been verified 

 by others. 



In January 1886 we had a wide-spread and heavy rainfall, and 

 also an auroral display seen only at Hobart, but which was suf- 

 ficiently powerful to totally suspend communication over all the 

 telegraph lines situated between Tasmania and the China coast. 

 This sensitiveness upon the part of the electric currents to auroral 

 excitation is not novel, for long experience on the telegraph wires 

 of Scandinavia has shown that there is such a delicate sympathy 

 between them that the electric wires there manifest the same 

 daily and yearly periods of activity as those that mark the 

 auroras. The current that reveals itself in fire in the higher 

 regions of the atmosphere is precisely the same current that 

 plagues the operator in his office. Therefore, in the records of 

 these troublesome earth-currents, now being accumulated at the 

 Observatory by Mr. Ellery, we are collecting valuable data, 

 which may possibly enable the physicist to count the unseen 

 auroras of the Antarctic, to calculate their periods of activity 

 and lethargy, and, again, to check these with our seasons. But 

 it need han.'ly be said that the observations, which may be 

 NO. 1094, VOL. 42] 



made in the higher latitudes and directly under the rays of tlu 

 Aurora Australis, will have the greater value, because it is only 

 near the zone of maximum auroral intensity that the phenomena 

 are manifested in all their aspects. In this periodicity of tht; 

 southern aurora I have named the last scientific problem to 

 which I had to direct your attention, and I would point out that 

 if its determination should give to us any clue to the changes in 

 the Australian seasons which would enable us to forecast their 

 mutations in any degree, it would give to us, in conducting those 

 great interests of the country which depend for their success 

 upon the annual rainfall, an advantage which would be worth, 

 many times over, all the cost of the expeditions necessary to 

 establish it. 



Finally, there is a commercial object to be served by 

 Antarctic exploration, and it is to be found in the establishment 

 of a whaling trade between this region and Australia. The 

 price of whalebone has now risen to the large sum of ;,^2O0O a 

 ton, which adds greatly to the possibilities of securing to the 

 whalers a profitable return. Sir James Ross and his officers 

 have left it on record that the whale of commerce was seen by 

 them in these seas, beyond the possibility of a mistake. They 

 have stated that the animals were large, and very tame, and 

 that they could have been caught in large numbers. Within the 

 last few years whales have been getting very scarce in the Arctic, 

 and in consequence of this two of the most successful of the 

 whaling masters of the present day. Captains David and John 

 Gray, of Peterhead, Scotland, have devoted some labour to 

 collecting all the data relating to this question, and they have 

 consulted such survivors of Ross's expedition as are still available. 

 They have published the results of their investigations in a 

 pamphlet, in which they urge the establishment of the fishery 

 strongly, and they state their conclusions in the following words. 

 They say: — "We think it is established beyond doubt that 

 whales of a species similar to the right or Greenland whale, 

 found in high northern latitudes, exist in great numbers in the 

 Antarctic seas, and that the establishment of a whale fishery 

 within that area would be attended with successful and profit- 

 able results." It is not necessary for me to add anything to the 

 opinion of such experts in the business. All I desire to say is 

 that if such a fishery were created, with its head-quarters in 

 Melbourne, it would probably be a material addition to our 

 prosperity, and it would soon increase our population by causing 

 the families of the hardy seamen who would man the fleet to 

 remove from their homes in Shetland and Orkney and the 

 Scotch coasts, and settle here. 



In conclusion, I venture to submit that I have been able to 

 point to good and substantial objects, both scientific and 

 commercial, to justify a renewal of Antarctic research, and I 

 feel assured that nothing could bring to us greater distinction in 

 the eyes of the whole civilized world than such an expedition, 

 judiciously planned and skilfully carried out. 



QUARTZ FIBRES} 

 "DEFORE I enter upon the subject upon which I have to 

 -'-^ address you, I wish to point out that, quite apart from any 

 deficiency on my part which will be only too apparent in the 

 course of the evening, it is my intention to commit two faults 

 which may well be considered unpardonable. In the first place, 

 I shall speak entirely about my own experiments, even though 

 I know that the iteration of the first personal pronoun for the 

 space of one hour is apt to be as monotonous to an audience as 

 it is wanting in taste on the part of a lecturer. In the second 

 place, I am going almost to depend upon the motions of a spot 

 of light to illustrate the actions which I shall have to describe, 

 in spite of the fact that it is impossible for an audience to get 

 up any enthusiasm when watching the wandering motion of a 

 spot of light the result of the manipulation of a mystery-box, 

 of which it is impossible to see the inside. These, however, are 

 faults which are the immediate consequence of the nature of my 

 subject. 



Physicists deal very largely with the measurement of extremely 

 minute forces, which it is of the utmost importance that they 

 should be able to measure accurately. Now forces may be 

 considered under two aspects. It may be that the force which 

 is developed and which has to be measured is a twist, in which 

 case the twisting force may be applied to the end of a wire 

 directly, when the amount through which that wire is twisted is 

 a measure of the twisting force. Or the force may be a direct pull 



' Lecture delivered by Prof. C. Vernon Boys, F.R.S., on September 

 8, i8go, at the Leeds meeting of the British Association. 



