Dec. 22, 1887] 



NATURE 



173 



views on the formation of images in the microscope had 

 received the advantage of his personal and later revision ; 

 but it is none the less due to the authors to acknowledge 

 the credit that is justly theirs, for the very early recogni- 

 tion of the value of his investigations ; and for the earnest 

 manner in which they endeavoured to embody those in- 

 vestigations in a popular text-book at a date (1877) when 

 hardly more than the barest outlines of the subject had 

 been published by Prof. Abbe himself 



We note that the authors give the preference to day- 

 light over lamp-light, believing that it exerts less strain 

 upon the eye. We suspect that the majority of English 

 observers, especially at continuous work, and with high 

 powers, will be inclined to reverse this judgment. Ex- 

 tremely white and intense light can be obtained from good 

 modern lamps, and, unHke daylight, it is unvarying, devoid 

 of caprice, and easy of manipulation. But this is a matter, 

 perhaps, in some sense subjective, and not of vital moment. 



The world of science generally and of microscopical 

 science in particular, is deeply indebted to Mr. Crisp for 

 initiating this translation, which, we have taken pains to 

 find, is most carefully done ; and to Mr. Mayall for his 

 part of the laborious undertaking. We can only hope, in the 

 interests of English and American science, that it will find 

 a large circle of careful readers on both sides of the At- 

 lantic ; and we warmly concur in the hope expressed in 

 the preface, " that the volume may be supplemented be- 

 fore long by an English version of the further researches 

 in microscopical optics by Prof. Abbe, of Jena, which 

 have extended so much our knowledge of the matters 

 dealt with in Naegeli and Schwendener's work." 



W. H. Dallinger, 



THE CRUISE OF THE " DIJUMPHNA." 

 The Cruise of the "Dijufnphna." With Reports 0/ the 

 Zoological and Botanical Results of the Voyage. By 

 R. Bergh, J. Deichmann Brandt, J. Collin, H. Hansen, 

 T. Holm, C. Jensen, G. Levinsen, C. Liitken, L. K. 

 Rosenvinge, M. Traustedt, and N. Wille. (Copenhagen, 

 1887.) 



THE Danish Arctic Expedition of 1882-83 owes its 

 initiative to its able commander, Lieut. Hovgaard, 

 of the Danish Navy. This enterprising officer, whose 

 practical experience of Arctic navigation gave great 

 weight to his opinions on the subject, had early in 1882 

 published a pamphlet, entitled " Suggestions for a Danish 

 Polar Expedition," in which he advocated his own theories 

 regarding the distribution of land and water in the Arctic 

 regions, and the feasibility of finding some hitherto 

 untried route for circumpolar exploration. 



In response to his appeal for means to test the 

 accuracy of his opinions, a private individual, Herr 

 Gamel, of Copenhagen, placed at his disposal a screw- 

 steamer, since known as the Difuinphna, whose equip- 

 ment for Polar explorations and scientific observations 

 was supplemented at the expense of the Danish Ministry 

 of Marine. 



Thus well prepared, the Expedition left the Copenhagen 

 Roads, July 18, 1882, but unfortunately the Difumphna 

 early encountered ice, which was found to be so dense 



south of Cape Tschernui Noss that it was only after a 

 delay of more than four weeks off" the south-west coasts of 

 Nova Zembla, that an entrance could be made into the 

 Sea of Kara, where, in accordance with Hovgaard's antici- 

 pations, the water was clear. The hopes of success to 

 which this fact gave rise proved, however, delusive, for 

 the ice began to re-form so rapidly that, within a few 

 days of their passage into the Kara Sea, it had become 

 apparent that the Difumphna was fast bound for the 

 coming winter ; and it was only after nearly a twelve- 

 month's detention that the ice began to loosen, when the 

 westerly trend of the drifts carried the ship, in the August 

 of 1883, back towards the entrance of the Sea of Kara. 

 With a broken screw and failing supplies, there was no 

 alternative but to renounce all hope of advancing further 

 east, and, accordingly, by help of sails the Difumphna 

 began its homeward voyage, which was so retarded by ice- 

 drifts and storms that the harbour of Copenhagen was not 

 reached till December 3, 1883. 



In the course of the winter the sun remained below the 

 horizon from November 20 to January 22, the temperature 

 at the latter date falling as low as - 47""9 C. ; while there 

 was constant danger of being crushed in the ice, or car- 

 ried with moving drifts on the shore. Yet, notwithstanding 

 these drawbacks, the trawl and dredge were diligently 

 used at 190 diff'erent stations, ten of which were in the 

 Jugor Schar and in Olenje Sound, off the south-west 

 coast of Nova Zembla. Most of the deep-sea soundings 

 were carried on in the Sea of Kara, between 69° 42' N. lat., 

 64° 45' E. long., and 71° 46' N. lat., 65° 14' E. long., 

 within which limits the ship was moved forward and 

 backward by the ice-drifts. This ground proved specially 

 rich, and Herr Holm, the efficient naturalist of the 

 Expedition, was able to bring home an exceptionally 

 large number of well-preserved botanical and animal 

 collections, which now form a valuable addition to the 

 contents of the Danish National Museum, to which they 

 have been generously ceded by Herr Gamel, the owner 

 of the Difumphna. 



Herr Holm's report of the flora of Nova Zembla, which 

 he examined at twelve distinct localities during the 

 Difumphna' s long detention off" the coast, confirms the 

 statement of Von Baer as to the abundance of vegetation 

 on the tundras, but he differs from him in regard to the 

 mode in which plants found their way into these high 

 latitudes. According to Von Baer, to whose report of his 

 scientific mission, undertaken for the Russian Govern- 

 ment in 1837, we are indebted for our first acquaintance 

 with the Nova Zembla flora, its plants have all been 

 stranded from neighbouring shores through the agency of 

 drifting ice. Herr Holm, on the other hand, believes 

 that a few forms may be survivals from pre-glacial periods, 

 but that the presence of the majority is due partly to the 

 agency of birds, of which large numbers, more especially 

 Tringa and other waders, frequent the shores, and partly 

 to the winds, and to ice-drifts. Insects are too rare to 

 affect the question of plant-propagation, and his observa- 

 tions—that most plants on the tundras have the corolla 

 directed upwards, while pendent or drooping forms are 

 very rare, and that the majority are scentless, and of one 

 uniform colour — appear to favour these views ; although it 

 is possible that the existing flora may also to some extent 

 be due to self-fertilization. 



