Oct. 23, 1879] 



NATURE 



6ir 



Stor Fjord, the expedition made for Ice Fjord, which, at 

 its east end, sends off three branches. A careful exarnina- 

 tion was made of several parts of the coast of this fjord, 

 and in the neighbourhood of the North Fjord Norden- 

 siyold collected a large number of triassic fossils, among 

 them large nautilus-like shells and fragments of bones, 

 some of which were thought to have been four feet long, 

 belonging to crocodile-like animals. While in Ice Fjord, 

 the expedition met with Mr. Birkbeck's yacht Sultana, 

 " a beautiful but fragile nutshell," having among others 

 on board. Prof. Newton. Here also a water-mark was 

 fixed. After leaving Ice Fjord, the Axd Thordsen suc- 

 ceeded in reaching Stans Foreland, a large island to the 

 south-east of the main island, having on its south the 

 Thousand Islands. 



" Fortunately it appeared that the discouraging descrip- 

 tions of the fogs prevailing here are properly applicable 

 to the Thousand Islands, comparatively clear weather, on 

 the contrary, being common in the inner part of the 

 fjord. Here, as at many other places on Spitzbergen, 

 may be found cloudless skies and sunshine, while an im- 

 penetrable fog lies at the mouth. The cause of this is to 

 be sought for in the course of the marine currents. While 

 an arm of the Gulf Stream, as the masses of drift-wood 

 heaped up at South Cape and the Thousand Islands 

 show, at least during a portion of the year, flows past the 

 southern part of West Spitzbergen and Stans Foreland, it 

 is the Arctic current entering from Helis Sound and 

 Walter Thymen's Strait, which principally prevails in the 

 interior of Stor Fjord. There is, therefore, no drift-wood 

 to be met with on the shores of this fjord, 'on which 

 account it is necessary on boat voyages to carry a supply 

 of fuel. During boat voyages along the north coast of 

 Spitzbergen one may, on the contrary, nearly always 

 reckon on finding in the neighbourhood of the resting- 

 place dry and excellent material even for a large log fire." 

 The west coast of Stor Fjord is occupied by enormous 

 glaciers, which go down to the sea and are only inter- 

 rupted by black, often conically-shaped mountain tops. 

 On the east coast, on the contrary, between Whales' 

 Point and Helis Sound, there is only a single consider- 

 able glacier, the coast being formed of a continuous rocky 

 wall, which rises almost directly from the sea to a snow- 

 free plateau of about i ,oco feet in height. At the foot of 

 this wall there are here and there grassy slopes, which 

 form the finest reindeer grounds on Spitzbergen. The 

 west coast both of Stans Foreland and of Barents Land 

 was examined as far north as the extremity of the fjord. 

 In connection with this part of the expedition's work, 

 some interesting remarks are made on the character of 

 the Spitzbergen glaciers :— 



" When icebergs are spoken of in the region of Spitz- 

 bergen, it ought to be remembered that what is meant 

 is large blocks of ice which fall down from the perpen- 

 dicular sea faces of the glaciers. Though these blocks 

 are often exceedingly large, they cannot in any way be 

 compared with the icebergs in the Greenland waters, 

 which are said to reach a height of 1,000 feet. The 

 glaciers on Greenland near the sea are indeed higher 

 than on Spitzbergen, but this dissimilarity is not suffi- 

 ciently great to explain the great difference in the dimen- 

 sions of the glaciers at the two places. There is great 

 probability in Prof. Edlund's hypothesis that the larger 

 icebergs are formed by blocks of ice falling down from a 

 glacier coming in contact in their lower parts with an 

 over-cooled stratum of water which, as is well known, in 

 contact with actual ice immediately assumes the solid 

 I form. For any such over-cooled stratum of water can, on 

 i account of the Gulf Stream, only exceptionally occur on 

 - the coasts of Spitzbergen, while the contrary is the case 

 in the waters of Greenland, which are taken up almost 

 exclusively by the Arctic current. The ice seeds which 

 have fallen from the glaciers thus find only at Greenland 

 j a suitable soil for their further development, only there 



do they grow to enormous ice-masses, which are so often 

 the cause of the navigator's astonishment and alarm." 

 (77i be continued) 



HE RING'S THEORY OF THE VISION OF 

 LIGHT AND COLOURS 



A FEW years ago Herr Ewald Hering, Professor of 

 Physiology at Prague, communicated to the Imperial 

 Academy of Sciences at Vienna a series of six papers 

 propounding a new explanation of the physiology of 

 vision, so far as concerns the perception of light and 

 colour. The papers were subsequently collected and 

 published in a separate form,' and have had a wide 

 circulation. The author is well known by his researches 

 on various 'physiological subjects, and has long devoted 

 attention specially to the phenomena of vision, many of 

 his views having been discussed at much length in Helm- 

 holtz's " Handbook of Physiological Optics," published 

 between 1856 "and 1866. 



The principiles developed in the papers in question have 

 attracted much attention on the Continent, and, it is 

 believed, have been thought well of by many competent 

 authorities. So far as I know, however, no account 

 of them, beyond meagre notices of a few lines, has 

 yet been made accessible to English readers. It is 

 highly desirable, both for the reputation of the author and 

 for the information of those of our countrymen who are 

 interested in the subject, that this want should be supplied, 

 and I propose now to offer to the readers of Nature 

 an abstract of Prof. Hering's theory, sufficiently explicit 

 to enable its general nature to be understood, but at the 

 same time not so full as to supersede reference to the 

 work itself by those who desire to appreciate the reasoning 

 more thoroughly. 



The theory of the perception of light and colours at 

 present best known and most generally adopted, is the 

 one formed on the views of Thomas Young, and further 

 elaborated by Helmholtz in his great optical work— hence 

 called the Young-Helmholtz theory. That which Hering 

 proposes to substitute for it may rather be considered as 

 an extension and an improvement than an opposing 

 theory, inasmuch as its chief aim is, by the introduction ot 

 additional elements, to account for phenomena which,, 

 according to the previous hypotheses, are left obscure, or 

 receive insufficient explanations. This consideration will 

 insure for the theory a more favourable reception than 

 if its object were completely to overturn received ideas. 

 It is not, however, intended here to offer any discussion 

 of the theory; we have only to state what its general 

 features are. 



In the first place, it should be explained that the theory 

 is developed chiefly in regard to the vision of black and 

 white, and their mixture, gray. The subject of colour is 

 introduced afterwards, following out the same principles. 



The reasoning is founded for the most part on a class 

 of visual phenomena of a subjective nature, such as thfr 

 effect of contrasts, appearances after looking steadfastly at 

 objects, and so on. These phenomena have long been 

 considered important in regard to the theory of vision, 

 and they are treated of by Helmholtz at much length. 

 The author, however, contends that the endeavours made 

 to explain them have been hitherto imperfect, inasmuch 

 as it has been necessary to call in for this purpose the 

 aid of psychological considerations, such as the effect ot 

 imagination and other causes of deception. As he 

 expresses it, on erery other page of a professed treatise 

 on physiological optics, one finds the mental judgment 

 invoked as a dcus ex machind to explain any sort of difti- 



• " Zur Lehre vom Lichtsinne." SeAs Miltheilungen an die kaiserL. 

 Akadi-mic der VVisstnschaften in Wicn. Von Ewald Hering, Profeuor der 

 Pbysiologie in Prag. Zwciter Abdruck. Wien, 1878. 



