184 



KNOWLEDGE. 



[August, 1901. 



drifting irregularly with the ice, the elements of uncertainty 

 are of the same magnitude throughout, a small drift giving a 

 considerable difference in longitude and local time. For the 

 rating of the chronometers for use with the half seconds pen- 

 dulums, observations made by the above method were useless, 

 and consequently oljservations of the solar eclipses of 1894, 

 April 5, and 1895, .March 25. as well as observations of lunar 

 distances and eclipses of Jupiter's Satellites were employed for 

 the determination of Greenwich time. During the famous sledge 

 journey of Nansen and .Johanseu it happened once that, the 

 working day of the men had been longer tlian that of tiie 

 watches, with the result that both watches ran down, and hence- 

 forth the determination of longitude on this journey became 

 more difficult, for in addition to this the tables of lunar dis- 

 tances had (probably on account of portability) been cut out of 

 the " Nautical Almanac," and although Nansen was continually 

 on the look out for the moon during her period of visibility he 

 was only able to make one observation, in consequence of the 

 difficulty of picking up the moon by the naked eye on the 

 jmle sky, with the strong redection from tlie immense white 

 surface of ice. All the observations involving altitude were 

 corrected by a refraction table with an extension of the tem- 

 perature table down to — cO" C, calculated by Bcssel's for- 

 mula, and observations were made on the sim and certain 

 stars at temperatures ranging from — l-i'4° C. to —500° C, 

 so that some idea of the accuracy of the prepared table can be 

 made. 



Memoir VII. contains the magnetic observations made by 

 Oapt. Scott-Hausen during the voyage of the " Fram," as well 

 as the few result* it "as possible to obtain on the sledge 

 journey : it has been prepared by Prof. Aksel M. Steen of Chris- 

 tiana, "and Prof. Ad. Schmidt of Gotha has increased the scien- 

 tific interest of these results by calculating the theoretical values 

 of the magnetic elements for all localities where magnetic obser- 

 vations were nude. Dr. Schmidt's computed values are, how- 

 ever, for the epoch 1885, whilst the observations were made 

 during the period 1893-1896. These observed results are tabu- 

 lated, and the O — C"s for declination, horizontal force, and in- 

 clination given in adjoining columns. The differences are in 

 some cases large, e.g., the declination varies from —5° to +10°, 

 but bearing in mind that they are for different epochs, and thiit 

 they are uncorrected for diurnal variation, the observations show as 

 close an agreement with theory as might reasonably be expected. 

 Observations were made at 225 different places on 194 days, 

 giving 70 declination, 99 horizontal intensity, and 80 dip results. 

 The instrument by which the observations were made was specially 

 designed by Dr. Xeumayer for the conditions to be encountered, 

 and was a combination of the Neumayer Declinatorium and the 

 Fox Circle. As in all high latitudes magnetic storms were 

 somewhat frequent, and during 1^ liours on 24 November, 1894, 

 the declination needle was pei*tiu*bed through 2fi°. Captain Scott- 

 Hansen does not, however, seem to have made any systematic 

 observations for diurnal variation, but when it is remembered 

 that the observations were frequently made with instruments 

 mounted on an ice pillar and out in the open, ever liable to 

 an attack from bears, the result,s are highly creditable. One 

 reads that as a defence against bears a weapon, generally a 

 revolver, was always at hand, though of course at a sufficient 



distance not to influence the I'eadings. 



» 



llemoir 'VIII. deals with the pendulum observations, and has 

 been preiiared by Prof. O. ]'l Schitz. The pendulums were of 

 C'ol. von Steini'.ck's type, such as has been used by him on 

 the Austrian ililitiiry Survey, i.e., lialf-seconds pendulum of 

 invariable length. In a journey such as the " Frani's," oppor- 

 tunity did not exist for setting them up on the solid eartli, 

 and they were accordingly swung on the. shi]) when drifting 

 in the ice. and also on the ice itself. Sueli a proceeding would 

 bi' highly satisfactory as being free from local influence due 

 to mountains on high land, if it could be .satisfaet(u-ily proved 

 that (he ice was rigid enough. The ob.servations. however, are 

 llu' Krst tliat have ever been taken at sea as it might be called, 

 and show that there is nothing abnormal about the force of 

 gravity over the polar basin, the result beiec g "= 983'147 for 

 nieun latitude HH", and, llievctore, I'rof. Seliitz assumes that 

 it is normal over all the great oceans. All the swings appear 

 to have been made at the normal pressure : it would, perhaps, 

 liave been more interesting if they had been ma/le at the usual 

 pressure of 50 mm., and swung over 24 liours, but the chrono- 

 meters could not be rated to the ideal accuracy, and the ice 

 changes would, no doubt, have been greater. Cajit. Scott-Hansen 

 is to be commended on doing the right thing under the cir- 

 cumstances, and thus securing valuable results. The amount 

 of work to show by so small a band ;ls that on board the 

 " Fr.'ini " fills one with admiration, and at least one could not have 

 found time to .suffer from ennui — Capt. Sigurd Scott Hansen — whom 

 Nansen deservedly praises for the excellent work done by him 



under difficult conditions, and brought together in the three 

 Memoirs cited above. 



"The Birds of Siberi.v." By Henry Seebohm, f.l.s., f.z.s., 

 F.R.G.s. (Murray.) Illustrated. *12s. net. — The late Mr. 

 vSeebohm's two delightful books " Siberia in Europe " and 

 " Siberia in Asia," have long been so rare and ditficult to 

 obtain that this volume which is practically a reju-int of these 

 books of travel will be very welcome to those who are not 

 the fortunate possessors of the original volumes. The first 

 journey to the Kiver Petchora was, we believe, planned and 

 originated by Mr. J. A. Harvie-Brown, who was Mr. Seebohm's 

 companion on the exiJedition. In the Petchora delta the grey 

 l^lover, the little stint and Bewick's swan were found breeding, 

 and well authenticated eggs were brought home. The eggs of 

 Bewick's swan had never before been discovered, while those 

 of the grey plover and little stint were almost unknown. In 

 the second" journey, accompanied by Captain Wiggins, Jlr. 

 Seebohm explored the great river Yenesei, from Krasnoyarsk to its 

 mouth. The eggs of many little knoivn birds were obtained, 

 and a large and interesting collection of birds was made. At 

 the time of the author's journeys (1875 and 1877) there was no 

 railway east of Moscow, and enormous journeys by sledge in 

 winter" had to be undertaken. The book by no means deals 

 exclusively with birds. The sledge and boat travelling are 

 vividly described ; there are many interesting observations on 

 the natives of Siberia, and the breaking up of the ice on the great 

 rivers is graphically depicted. The jiresent volume has been 

 only slightly edited, and several inaccuracies and repetitions 

 have been allowed to remain. A few notes, comprising chiefly 

 Mr. Popham's ornithological discoveries on the Yenesei, have 

 been added to the text. We do not admire the cover, but the 

 inside of the book is well printed, and two fascinating books 

 of tiavel are now brought within easy reach of those interested 

 in northern regions. 



" Thk Elkments ok D.arwinism." By A. J. Ogilvy. 

 (Jarrold & Sons.) 2s. 6d. — It is impossible for anyone who is 

 not a naturalist by instinct and observation to appreciate to 

 the fullest extent the structure upon which evolution depends 

 for .supjDort, whether it be natural selection or acquired 

 characteristics. A broad and general knowledge of the con- 

 ditions and processes involved can be obtained by reading, and 

 there are many people who are satisfied with such a view. 

 Mr. Ogilvy gives a survey of Darwinism suitable for readers 

 of this class. His book is a primer which can be understood 

 by those who are unfamiliar with the technicalities of natural 

 history, even though sometimes they may not see the real signi 

 ficariee of the facts descrt'oed. Every cultivated person ought 

 to have grasped the simple statements and principles expounded 

 in (his little volume, because the knowledge would make them 

 realise their responsibilities in the natural and social worlds. (?)f 

 course, as the book only surveys Darwinism it is not a com- 

 plete statement of the doctrine of evolution, and it may lead 

 to tile idea that tile two terms are synonymous. But sufficient 

 is said to show the reader that natural selectiim is not the only 

 road to evolution, and interested students will follow up the 

 subject in other books. Dr. Wallace looked through Mr. Ogilvy 's 

 book before publication, and the contents have his general 

 ajiproval, though the author alone is responsible for the treat- 

 ment of the suDJect. 



" Element-\ry Pr.\c'tic.\l il-\THEMArics." By JI. T. Ormsby. 

 (E. & F. Spon.) 7s. 6d. net. — A great change is taking place 

 in (ho methods of teaching mathematics. The old idea that 

 only those parts of the subject of which a student knows the 

 rigid proof should be used by him is becoming discredited. Thi' 

 opinion is gaining ground that it is advantageous to teach 

 students, especially practical men engaged in engineering and 

 (lie constructive arts, the application of mathematical results, 

 leaving the f<n'mal steps by which such formula; are arrived 

 at to the professional mathematician. Just as in ordinai'y life 

 it is not considered necessary for every person who carries a 

 watch to understand its mechanism before telling the time of 

 day, it is very reasonably argued that an engineer should know 

 how, for example, to simplify his calculations by the use of 

 logarithms, even though he may be ignorant fif the |:iroof of 

 the Binomial Tlu-ort-m. This view of the teaching of mathe- 

 nraties has recently received otficial sanction by the publication, 

 in the " Directory " of the Board of Education, of a Practical 

 Mathematics Syllabus. It is to meet the requirements of students 

 such as those who iiresent themselves for the South Kensington 

 examination that ilr. Ormsby has written Iiis book. He has 

 included in it all (bos/ parts of arithmetic, algebra, trigonometry, 

 geometry, and tlu- calculus, which are frequently emjiloyed in 

 the workshop, and while using great care to prevent the formation 

 of misconceptions on the part of the reader, lu' has kept steadily 

 in view those ))roblema and theorems of constant use in every- 

 day practice. Graphic work, especially the plotting of curves, 



