116 



KNOWLEDGE ♦ 



[July 11, 1882. 



Ifttnd to tf)f (EiJitor, 



[n* SJitor dcti notloIJkimtflfrtfponsibltforthtopiniontofiui 

 M* camnot ^ujrrl^ikf tc return montitcriftt »r to correryotid triik their vrittrt. All 

 eammnmir^liotu ,\o»U hi at ikort v rotnble, coniiittntlf kH\ full and clear $tiilf 

 mnt> of Ike writer; ■ni»i«.«.] 



All EJtlor^-il r<mmnniealiont Atmld U addrn$ed lo tke Fdilor qf KitowurGB; 

 all Bneam communitaliom to Uu Pnhluker; at Ikl OJtce, 74, Orial V«<'"- 

 •fr.W. H'.C. 



All Brmjttcneu, Ckequei, and Potl-C>/flct Ordert ikould be made fat/able to 

 lie— re. Weman t Sone. 



*,• All lettrrt to tke Sdilor rill he Ktimberrd. Tor eonrrmrnce of rrferenee, 

 ccrreejonlenta^ wktn referring to anj letter^etill oblige by mentioning He number 

 m%d tke F^ge on tekiek it appeare. 



•'In knowlrdpe, that mui only is to be coDtprr.ni»d and dpppised who 



itate of trajivition Nor is there aDylhing more adverse I 



than flxily of opinion."— farojajr. 



" Show me a Duu who makee no miBtakee, and 1 will ehow you i 

 haa dose nothing." — Liebig. 



TERRESTRIAL MAGXETISM. 



[Wc have received an important communication from Professor 

 Tromholt, of Bergen, of which the following is a translation. — Ei).] 



I beg to announce to you that next autumn I intend to propose 

 to the Norwegian Government the formation of an establishment 

 for investigating and observing the Aurora Borcalis and otlior 

 phenomena of terrestrial magnetism. With your permission, ^f. 

 I'Attroni^me, in communicating this project to yon and reriuesting 

 your counsel, I will indicate in few words the motives which have 

 led mc to seek the realisation of this idea, in many respects a new 

 one. 



The theory of terrestrial magnetism is one of the i)roblems 

 which offers to natural science the strongest claims to examination. 

 If science has not been able as yet to solve more than a email por- 

 tion of the numerous problems belonging to this field ot research, 

 she has nevertheless been able at each step to prove more and more 

 clearly the enormous importance of the phenomena of terrestrial 

 magnetism in regard to the physical relations of our eartli. By 

 the discovery of a connection existing between these phenomena 

 and events on the sun's surface, the question has acquired cosmical 

 significance. 



It would be useless, 3/. I'Astrotiome, to recall to you the great 

 and important part played by the forces of terrestrial mag- 

 netism in the whole physical life of the earth, in their changing 

 state, and their various periods, whether they present themselves 

 in the perplexing )i!ay ot the polar light, or whether they speak in 

 the changing movements of the magnetic needle, or by their in- 

 floence on the telegraphic network of whole countries. 



No country in Europe, perhaps in the whole world, offers such 

 favourable conditions as Norway for the study of these phenomena. 

 Lying between the fifty-eighth to the seventy-first parallels of 

 north latitude, she extends farther north than any inhabited 

 country. She is nearer the seat of magnetic disturbances than 

 any part of the European continent. The maximum zone of the 

 aurora boreali.^ crosses the north and north-west portion of the 

 country. A continuous network of telegraphic wires extends from 

 its northern and its southern extremity. The telephonic lines of 

 Drontheim and Bergen are nearer the pole than any on the whole 

 earth. 



There is thus no country to which the duty of taking an ener- 

 getic initiation in the study of the mysteries ot terrestrial mag- 

 netism more directly presents itself. 



Having recognised these nnmerons advantages, neglected till 

 now, I have tried, during the few past years, to undertake, myself, 

 and at my own expense, a part of the great work which stiil re- 

 mains in this field, as yet scarce touched. In the antnmn of 1878, 

 I, for the first time, caused to be distributed in all parts of Norway, 

 an invitation leading (Acto de la Roci<;t£ dos Sciences of Chris- 

 tiana, IS80, No. 6) to the contribution of 8.(9 observations of 1.5). 

 aarr.ra.1, taken between September, 1878, and April, lb70, from 132 

 stations, principally in Norway. 



This resntt enabled mo to prove that the aurora is a pheno- 

 menon occurring much more frequently, oven outside the Polar 

 regions, than is supposed at present, and that in a territory like 

 Norway it seldom fails to occur even in a year of minimum 

 frequency. 



Counting from this modest beginning the plan has developed 

 itself raj^idly. Not only Sweden and Denmark, but Finland, 

 I'lijlaiiil, (iicenlnnd, and Iceland, are now included in tlio field of 

 111 all. in. The complementary work relating to the observations 

 r I i , iMiiter of 1879-80, although long since finished, has not yet 

 I ■ rn [iiiLlishod. This series is much more extended and complete 

 tliiin llint of the former winter, and contains l.GOD observations of 

 200 auroras (boreal) taken from 357 stations. The material obtained 

 during the winter of 1880-81 is much richer oven than that of the 

 preceding winter ; it includes 5,200 observations of about 300 

 nnroras taken at 675 stations. The result for tho winter of 1881-82 

 will probably bo still vaster. I correspond, at this present time, 

 with from 1,000 to 1,500 observers of all the northern countries of 

 Euro])e. 



As a supplement to these observations of the aurora borealis, I 

 have been able to get records at some fifty telegraphic stations, 

 Swedish and Norwegian, of all disturbances occurring on tho lines, 

 with note of tho time, the force, tho direction, Ac. From this 

 work, material as vast and ns astonishing as that from auroral 

 obsei-vntions has been obtained, the tolegraphio disturbances 

 showing themselves as frequent as the auroras ; scarcely a day 

 passes in Norway without some disturbance on tho linos. As soon 

 as I shall have received tho observations of an entire year, I will 

 publish them, with an atlas showing carto-graphically tho telegraphic 

 disturbances of each day, the auroras, and the storms observed the 

 same day, noting time and place, as well as the extent of night 

 cloud over the whole field of observation. 



I have succeeded in constructing an apjiaratus, which, when 

 placed in connection with a telegraph wire, notes graphically all 

 the disturbing currents, according to their time, force, and direction. 

 This llheograph will soon bo in communication every night with a 

 telegraphic line, extending north and south, to a distance of about 

 1,100 kilometres (870 miles) which is not employed at night in 

 telegraphic work ; during the day it will bo connected with a 

 special tolophonic line. 



I may add that I shall pass next winter (September to April) at 

 Kautokeino in Finmnrk flat. G9' 1' N., long. 21" 0' East of Paris), 

 to make there, in connection with tho Norwegian polar station, 

 Bosekop, situated lOO.kilomi^lrcs (G2 miles) further north, observa- 

 tions with respect to tho parallax of tho aurora borealis. 



Although I have received all possible support and encouragement 

 from tho Government and scientific institutions of tho Northern 

 nations, it is evident that an organisation so extended and so com- 

 plete must end by exhausting tho energies of one man alono, 

 especially as I am obliged to devote tho greater part of my lime to 

 other labours. It is also clear that an entcrpriso arising only from 

 individual initiative cannot be pursued with ns much exactness and 

 perfection as when supported by a public institution. 



[Professor Tromholt proceeds to describe the nature of his plan 

 in so far as it depends on such support as ho hopes to obtain from 

 the Swedish Government. A in.agnetie institution is to bo estab- 

 lished at Drontheim, and will contain all suitable instruments, Ac, 

 &c. Professor Tromholt hopes to make it tho central jjoint for all 

 observations of auroras in Europe. It will also take charge of all 

 observations of telegraphic disturbances. " I am persuaded," pro- 

 ceeds Professor Tromholt, " that an observatory such as this will 

 bo able to render important services to science, and I hopo that the 

 realisation of this idea will bo received with joy by tho scientific 

 world."] 



I address this communication to you, if. V Aslronnme, and to 

 other recognised authorities in this department of science, that the 

 question may be submitted to your judgment. I bog that you will 

 communicate to mo your opinion of the merits of such an institution, 

 so that tho weight of your name m.iy help to support mo in my 

 efforts to realise my jjrojcct. If (which I do not doubt) tho idea 

 should meet with your approbation I shall also be much obliged to 

 you if you would be kind enough to give mo your opinion and advico 

 as to the organisation of the Institution. 



lloping to bo honoured by an early reply, which may bo expressed 

 in any Innguago yo>i may prefer, I have the honour to be, M. 

 I'Aiiironome, &c., &c. 



Borgcn, June, 1882. Soi'iifs Tiiumiioi.t. 



FIGURES OF FLUID-MOTION. 

 [■1G3] — I hopo you, like your renowned nci(;hbonr, Mr. Punch, 

 keep a regular staff of young men, to whom you turn over, like 

 Mr. F.'s aunt to Clennam, all tho crusts of yoiir daily toast. For 

 you, like all men of the Fifth Imperial potentiality (you like these 

 fine terms, Sir — so easy to read out loud, and so full in the mouth, 

 you know — " scientifically wrong and mathematically to bo mis- 

 understood," as yon beautifully express it in the gorgeous shino of 

 "our" Knowiedce'h first-page) ; you, Sir, I say, are doubtless as 

 much toasted as you care for. Let the young mon, then, make a 



