lO 



NATURE 



[March 3, 1910 



Messrs. Koefoed and Hclland-Hansen, yet no mention 

 of this veteran's name or work is made. Buchanan, 

 Nansen, Bruce, and others have also observed this 

 phenomenon. VVe doubt also if some of these old 

 observations are less exact than those of more recent 

 date. The Buchanan methods give, for instance, 

 observations of great exactitude, and certainly equal 

 to any of the most recent observations of the younger 

 Scandinavian school of oceanographers. 



Part ii. deals with instruments and methods; and 

 here useful discussion could be entered upon, as, for 

 instance, on the question as to whether one is able to 

 obtain results of greater accuracy with the more finely 

 graduated Richter thermometer on the deck of a ship 

 in the polar regions, with discomforts of mist, sleet, 

 snow, wind, and weather. A stronger marking and 

 coarser scale certainly in many cases will give more 

 accurate results than the very finely-graduated scale of 

 the Richter thermometer instruments, as the reviewer 

 knows by extensive work on board ship in all weathers 

 and almost all latitudes. The question of a ridge 

 rising to within about 400 fathoms of the surface is 

 discussed, but so far no absolute proof of this has 

 been obtained, owing to the great difficulty of pene- 

 trating the polar pack — some of the heaviest ice in 

 the world — between the north of Spitsbergen and the 

 east of Greenland. The Duke of Orleans has, how- 

 ever, come nearer accomplishing this important in- 

 vestigation than anyone else, for he obtained a more 

 complete line of soundings two degrees further north 

 in the middle longitudes of the Greenland Sea than 

 any previous navigator. 



The authors divide the Greenland Sea into three 

 areas : — 



(i) East — having high temperatures and salinities, 

 being influenced by the Gulf Stream. 



(2) Middle— a deeper region with mixed conditions. 



(3) West — a shallower region with low temperatures 

 and salinities, being influenced by the polar current. 



Plate Ixii. gives a chart indicating the stations of 

 the Belgica and those of other expeditions in the 

 Greenland seas and regions adjacent; but again we 

 miss the stations of Leigh Smith, 1870, those of 

 Bruce (S.Y. Blencathra of Major Andrew Coats), 

 1898, and those of the Prince of Monaco, 1898-g. Many 

 interesting problems are raised by the temperature, 

 salinity, and current observations made by the Duke 

 of Orleans and his stafl", and not least of them is the 

 theory of the Spitsbergen-Greenland ridge already 

 referred to, but it is impossible in this short review 

 to enter fully into all these questions. 



The zoology of the voyage, discussed by Prof. C. 

 Hartlaub, Messrs. D. Damas, E. Koefoed, and 

 M. J. G. Grieg, occupies more than a third of the 

 volume. The plankton work is very exhaustively and 

 thoroughly handled by Messrs. Damas and Koefoed. 

 Several dredgings in depths down to 750 fathoms 

 also secured a number of interesting benthoic forms. 

 The numerous inset maps and sectional diagrams and 

 tables are especially useful, bearing as they do on the 

 distribution of plankton. 



The plates by Werner and Winter maintain the 

 high reputation this firm has justly won. M. Edouard 

 M?rite's work is reflected throughout the natural 

 history of the expedition, though much of this excel- 

 lent artist's colour work only appears in the Duke 

 of Orleans's less technical work, "A Travers la Ban- 

 quise du Spitsberg au Cap Philippe." Dr. R^camier, 

 too, did much to make the voyage a success. 

 There are useful sketches of the new coast between 

 77° and 79° N., and some most excellent half-tone 

 blocks, many of w^hich show polar ice well ; the frontis- 

 piece is especially to be commended as "a thing of 

 beauty." One regrets to see that glazed paper is used 

 NO. 2105, VOL. 83 J 



instead of pure rag paper, which actually produces, 

 richer efl'ects and is infinitely more durable. 



Altogether the Duke of Orleans is to be most 

 heartily congratulated, not only for having personally 

 conducted all the above work, but even more so for 

 having placed the observations and material gathered 

 during the voyage into competent hands for examina- 

 tion and description, and for having spared no trouble 

 or expense in bringing out a volume which is second 

 to none as a monumental contribution to the oceano- 

 graphy of the Arctic Ocean. Too often polar expedi- 

 tions are dispatched by the help of men of means, but 

 these same people have little or no conception of 

 making use to the full extent of the material, obtained 

 with great care, toil, and trouble, on the return of 

 the expedition. The excellent work of many trained 

 men of science who accompany such expeditions is in 

 consequence largely wasted. Th4( Duke of Orleans, 

 however, has realised the full value of this subsequent 

 work, and the thanks of the scientific world is due to- 

 him for having seen it through so handsomely to the 

 finish. William S. Bruce. 



AEROPLANE STABILITY. 



IN 1896 I had the pleasure of attending a lecture 

 on naval architecture given before the British. 

 Association in Liverpool by the late Dr. Francis Elgar,. 

 F.R.S. I had learnt the theory of the metacentre in 

 my undergraduate days, but it came to me as a great 

 surprise to learn that this theory had only been evolved 

 after many ships had foundered, owing to want of 

 theoretical knowledge of their conditions of stability. 



I was interested in aerial navigation at the time,, 

 and although I had not got further than throwing 

 gliders, it was evident from their behaviour that a 

 mathematical theory of stability must necessarily be 

 of even greater importance in connection with aerial 

 navigation than with naval architecture, and I wrote 

 in Science Progress to the effect that if the future 

 development of artificial flight were not to be a repeti- 

 tion of the chapter of accidents by which naval archi- 

 tects had gained their theoretical knowledge, there 

 would be abundant work for mathematicians in reduc- 

 ing the conditions of stability to pure calculation. 



About the year 1903 I noticed that if a glider or 

 ether body is moving in a resisting medium, such as 

 air, in a vertical plane with respect to which it is 

 symmetrical, the small oscillations about steady motion 

 in that plane are determined by a biquadratic equation ; 

 and Prof. Love directed my attention to the condition 

 of stability given by Routh. Mr. W. E. Williams 

 was a post-graduate student in my department, and 

 with his collaboration we published a paper on "The 

 Longitudinal Stability of Aerial Gliders " (Proc. Royal 

 Soc, Ixxiii.), which was intended to direct attention to 

 the general method, and the importance of further 

 investigation, rather than to furnish a complete solu- 

 tion of the problem. 



Mr. Williams shortly afterwards obtained a so-called 

 " Research Fellowship " ; but " research " in this case 

 was interpreted as meaning practical work done in 

 a physical laboratory away from Bangor, so the award 

 had the effect of preventing the continuation of 

 original work on this important problem. On the 

 other hand, the necessity of providing, with one 

 assistant, classes in all grades of pure and applied 

 mathematics, and of devoting special attention to the 

 requirements of junior students whose knowledge of 

 the " first four books " and of arithmetic had been 

 neglected at school, left no time for me to carry on 

 the work single-handed. It is only since the com- 

 paratively recent abolition of these infra university 



