July 14, 18S1] 



NA TURE 



241 



the South African Chats, to some of which Mr. Seebohm 

 has applied his principle of hybridisation, as we are not 

 yet satisfied that the changes of plumage cannot be 

 accounted for by the more natural process due to age or 

 the season of the year. These few remarks will not, 

 however, detract from the sterling merit of Mr. Seebohm's 

 volume, which bears on every page the evidences of the 

 careful and exhaustive work which the author bestows on 

 every subject he handles. The eighteen coloured plates 

 are beautiful eximples of Mr. Keuleman's great talents as 

 a natural history artist, and the colouring is much more 

 satisfactory than in the last volume of this Catalogue, 

 issued by the British Museum. 



MAGNETIC AND AURORAL OBSERVATIONS 

 IN HIGH LA TITUDES 1 



LIEUTENANT WEYPRECHT, the noted leader of 

 the Austrian Arctic Expedition of 1872-74, whose 

 death is a great loss to science, recently published a little 

 text-book embodying the results of his wide experience in 

 .Arctic observation of mignetic and auroral phenomena, 

 which will be invaluable in pointing out to future observers 

 the precautions and requirements which only actual expe- 

 rience of Arctic life can suggest, and the arrangements of 

 apparatus and stores, which, once left behind, must be 

 done without ; frequently to the loss of opportunities for 

 observation which do not recur. It would however be 

 wearisome to the general reader to enter into details of 

 Arctic work, and no one to whom the matter is of practical 

 moment will omit reading the book itself. Some however 

 of the precautions suggested give so vivid an idea of the 

 difficulties and even the suffering which Arctic observers 

 have to meet in the cause of science, that we cannot 

 forbear a passing mention of them. 



In magnetic observatories, where iron is rigidly tabooed, 

 and uniformity of temperature is of the first importance, 

 stoves are naturally out of the question. In winter, when 

 the huts are thickly covered with snow, the temperature 

 should never fall below — 20° C. (- 4' F.), which, as 

 Weyprecht says, may be borne for some hours in suitable 

 clothing without severe suflering. Good fur garments are 

 naturally essential. The most difficult part is the suffi- 

 cient protection of the feet, that found most effectual 

 being very wide felt boots reaching to the knee, into 

 which the feet, clad in thick woollen stockings, are packed 

 with dry hay or straw. The hands are covered with 

 thick woollen gloves, and whenever they are not in actual 

 use are further protected by fur. In absolute determina- 

 tions however, which have to be carried on in a separate 

 hut, which is also used as an astronomical observatory, 

 and hence more open to the weather, the cold is not only 

 much more intense, but the fingers roust be left bare, or 

 at most covered with thin cotton gloves, on account of 

 the delicacy of the instruments. On two occasions during 

 the Tcgcttlioff Expedition such quantities of snow were 

 driven into the observatory through the crevices of the 

 shutters as, by loading one side of the telescope, actually 

 to throw it oft' its pillar. 



For absolute magnetic observations Weyprecht gives 

 preference to Prof. Lamont's portable theodol'te, which 

 contains in itself everything necessary for the determina- 

 tion of declination and horizontal and vertical intensity. 

 If however a fixed scale could be attached to the telescope 

 for rapid readings the instiument would be still further 

 improved. 



With regard to northern light observations, Weyprecht 

 repeats his important classification of auror.^1 forms given 

 in his NordliclUbcobachhingen. For observations on the 

 altitude of auroras, with a view to calculation of height, 

 he recommends a simple instrument consisting of a tube 

 with an eye-piece, movable in the magnetic meridian, and 



* " Prakttsche Anleitung zur Eeobachtung der P.larlichter und der m.Tg- 

 eiischeii Erbclie.nungen in hohen Bjeiten," v. n Carl Weyprecht, Schiffs- 

 tu tenant. (Wien, 1881.) 



with an altitude circle reading to A^ The tube must be 

 attached to the end of the axis, so as to be capable of 

 sweeping the entire meridian. The observations should 

 be repeated at short and regular intervals, and both the 

 upper and lower edges of the arches should be observed, 

 thus giving at once the mean altitude and the breadth of the 

 bands. If the "' dark segment " is visible, its mean height 

 and the azimuth of its summit must be observed, as it 

 probably indicates the direction of the origin of the 

 aurora. If a corona is formed the approximate position 

 of its centre must be observed. Another method of deter- 

 mining the position of the corona is by measuring the 

 direction of the rays of which the arches are formed. 

 This is best done by measuring their inclination from the 

 perpendicular in two azimuths 90' apart. If the tube we 

 have mentioned be provided with an azimuth circle and 

 cross-wires in the eye-piece with a position circle reading 

 to ^° this is readily accomplished, the perpendicular being 

 verified by observation of a plumb line. 



For spectral observations Weyprecht consiJers direct- 

 vision instruments of good dispersion the most suitable. 

 In low latitudes we have found a single bisulphide prism 

 and simple slit and eye-hole without lenses to answer 

 well, and if su:h an instrument were attached to the same 

 axis as the measuring tube, which would act as a finder, 

 we believe it would show fainter spectra than any direct 

 vision arrangement. We do not know however how it 

 would be aftected by Arctic temperatures. Weyprecht 

 does not mention any means of measuring the position 

 of the lines — the simplest is Piazzi Smyth's comparison 

 with the hydrocarbon spectrum of a spirit-lamp, and 

 another very good scale is the band-spectrum of air yielded 

 by a vacuum-tube fixed across the slit and made to fi.-'sh 

 as required. 



Weyprecht insists on the importance of further com- 

 parisons between the movements of the aurora and mEg- 

 netic disturbances, and points out the high interest that 

 would aho attach to ob.crvations of the earth-currents. 



H. R. Procter 



NOTTINGHAM (/NirERSIT)' COLLEGE 



THE fine building, auspiciously opened the other d:.y 

 as a college in the heart of Nottingham, represents 

 the last development of that all too tardy interest in 

 higher education which, in the more recent year:, 

 has originated the \'ictoria University in Manchester, 

 the Yorkshire College in Leeds, the Science College 

 in Newcastle (a flourishing off:,hoot of Durham Univer- 

 sity), the Mason Science College in Birmingham, and 

 others. 



It is gratifying to find in a new provincial centre, 

 with its varied activities and the usual temptations asso- 

 ciated with money-getting, an intelligent, if somewhat late, 

 appreciation of the thirst after knowledge for its own 

 sake, .-IS well as for that to which it may be profitably 

 applied, and a disposition to take generous means of 

 satisfying it. 



Of the inception and growth of the Institution we 

 need not here speak at any length. The elements of a 

 college were already in existence. For seven or eight 

 years past lecturers from Cambiidge have visited Notting- 

 ham and drawn large audiences. The Government 

 Science Classes were also highly appreciated. It is thus 

 estimated that no fewer than 1400 students will be ready 

 to take advantage of the instruction soon to be provided. 

 Nottingham, moreover, has possessed a public library 

 sin;e '186S, and this, along with the Natural History 

 Museum, greatly needed larger accommodation. From 

 the union and consolidation of these and other educa- 

 tional agencies under one roof where the conditions of 

 progress are much more favourable, excellent results 

 may be anticipated. A distinctive feature of the Notting- 

 ham College is that it has been built by the Municipal 



