Oct. 30, 1879] 



NATURE 



635 



the two famous meteors, one of which, weighing nineteen 

 tons is now in the Riks-Museum at Stockholm, and the 

 other, nine tons, in the Museum of Copenhagen. 



For the expedition of 1872-3 the Swedish government 

 provided a steamer, the Polhem, and a brig, the Gladaii, 

 which were accompanied by the Onkel Adam as tender. 

 Tromso was left on July 30, and Ice Fjord was again 

 visited, where a search was made in Coal Bay. Some 

 little time was spent at Fair Haven, on the north of the 

 island with the view of finding the place where the 

 D\varf Birch had been discovered in 1870 by Nathorst 

 and Wilander. After a long fruitless search, and when all 

 hope of finding it was given up and the return to the 

 boat commenced, its dark green leaves were at last 

 observed projecting from the surrounding moss. The 

 dwarf birch found here, the Betula nana, var. relicta, 

 Th. Fries, is believed to be a survival from the time 

 when Spitzbergen possessed a finer and warmer climate 

 than now. Its height, as found here, did not exceed 

 two feet, the thickest stem being from two to three 

 lines in diameter. After the return to Sweden it was 

 found by the help of the microscope that a stem of 

 this thickness was about eighty years old. The yearly 

 rings were exceedingly thin and faintly marked in 

 several specimens, and in some parts of the stem, 

 altogether indistinguishable. A well grown beautifully 

 flowering specimen of the Cardamine pratensis also 

 rewarded the search of the botanist, a find which was 

 specially welcome, because this plant, though pretty 

 widely distributed, is seldom found in flower on ;Spitz- 

 bergen. 



Leaving Green Harbour on August 4, the Polhem 

 proceeded on her voyage with the Gladan in tow, pass- 

 ing through the sound between Prince Charles Foreland 

 and the mainland and anchoring on the 7th in Fair 

 Haven for the purpose of regulating the chronometers 

 at the place where Sabine and his companions spent 

 three weeks in 1823, carrying on a series of physical 

 and astronomical observations. The place which is 

 situated on the south-western shore of the inner Norway 

 island still bears the name of Sabine's observatory, and 

 is distinguished by a great number of stones collected in 

 a circle. While here, Wijkander carried on a series of 

 magnetic observations at Sabine's observatory. Astro- 

 nomical observations were also made, and two and some- 

 times three boats were at work dredging from morning 

 till night. It ought also to be mentioned that on the 

 drift-ice which the Polhem had encountered a short time 

 before, Nordenskjold had found small quantities of dust 

 similar to that which he had discovered in the snow during 

 a snow-storm at Stockholm in December 1871. This dust, 

 which he believes to be of cosmic origin, contains metallic 

 iron, cobalt, nickel, phosphoric acid, and a colloid organic 

 substance. " However small and inconsiderable the 

 quantity of this substance may be in proportion to 

 the snow or water falling at the same time," he writes, 

 "it may yet play an important part in the economy 

 of nature ; for example, by means of the phosphoric acid 

 which it contains it may restore the fertility of tlic soil 

 impoverished by repeated harvests. This observation 

 ought also to be of great importance for the theory 

 of rneteors of the aurora, &c. Perhaps we should 

 inquire whether in this phenomenon we are to seek 

 the explanation of the abundance in which magnesia, 

 which occurs plentifully in meteorites, is found to exist 

 in certain distinct geological districts, and if an increase 

 of the earth's mass, which is certainly minute, but 

 which is going on continuously, ought not to produce 

 very considerable changes in the geological theories 

 now prevailing, which proceed on the supposition 

 that the globe is as nearly as possible unaltered in 

 mass since the first occurrence of plants and animals, 

 and that the geological changes have always depended on 

 changes of distribution in the mass over the surface of 



the earth, never upon the arrival from without of new 

 constructive material for our globe." 



While at Fair Haven the expedition was visited by 

 Mr. Leigh Smith in his yacht, who promised that he 

 would be among the first to look them up next summer. 

 After a long enforced delay in Fair Haven on account of 

 the ice, the expedition got away in September 1, but failed 

 in every attempt to reach the Seven Islands. Mussel 

 Bay, then, a small inlet off the east side of the mouth of 

 Wijde Bay was chosen as the winter quarters of the 

 expedition, and here all three vessels were ultimately 

 locked in the ice. One large building was erected on 

 shore besides magnetical, meteorological, and astronomical 

 observatories. During the whole of the stay of theexpedition 

 here regular observations were carried on in their observa- 

 tories. Provisions were short, and all had to be put on 

 allowances ; though scurvy broke out there was only one 

 death, and altogether the winter was a dreary one, in 

 spite of every effort to keep officers and men constantly 

 employed. 



Wijkander remained whole nights in his observatory 

 bravely defying the cold and patiently overcoming the 

 many difficulties attending astronomical observations 

 made in such circumstances. In the cold weather the work 

 out of doors was not stopped and the dredgings still went 

 on, it being of great importance to ascertain whether the 

 severe cold and the long darkness exercised any special 

 influence upon the marine animal and vegetable world. 



With the arrival of spring preparations were made for 

 the ice-journey to the north, but as we have said already 

 they did not get beyond the Seven Islands. Nordenskjold 

 makes some interesting observations on the rugged ice 

 which prevented him attempting to push further north- 

 wards. " The ice we thus passed is formed not of 

 colossal blocks or icebergs, but of angular blocks of ice, 

 not luaterworn, piled loosely over each other, so as to 

 form pyramids, or walls .of ice, up to thirty feet high, 

 which were so close to each other that the space betweerj 

 them was frequently not large enough for our tent. The 

 cause of the formation of these ice-walls, which were 

 also observed by Wrangel on the north coast of Siberia, 

 is probably to be sought for in the changes of volume 

 which ice undergoes when its temperature is changed. 

 According to Pliicker and Gcissler, the linear expansion- 

 coefficient of ice is = o"oooo528. If, therefore, ice of 

 o' C. be cooled to — 15^ C, cracks must arise which, for 

 1,000 metres, have a breadth of 32 inches. The cracks 

 naturally freeze together immediately afterwards, and 

 when the ice is again warmed, for instance to — 5° C, a 

 piiing-up must take place of 21 inches per kilometre. 

 During the course of the winter this phenomenon is 

 repeated innumerable times, one layer of ice being piled 

 upon another, till the whole ice-field forms a confused mass 

 of blocks of ice heaped up against each other. Similar 

 forces are also in operation in the crust of the earth, with 

 less intensity, indeed, in consequence of the smaller 

 expansion-coefficient of the rocks which compose it, and 

 the inconsiderablencss of the changes of temperature 

 which occur in them, and the cracks thus formed may 

 here come together again, provided no chemical or 

 mechanical sediment has been deposited in them, as is, 

 perhaps, often the case. On the other hand, the forces 

 operate in the earth's crust during millions of years, and 

 I doubt not that in the circumstances here noticed the 

 cause of the strata being contorted, dislocated, and thrown 

 over each other is to be sought for. This last, perhaps,, 

 to judge by the observations I had the opportunity of 

 making on the polar ice, happens far oftener than we 

 commonly suppose, and when it takes place there often 

 occurs no considerable disturbance in the original hori- 

 zontal position of the stratum. Certainly in most cases 

 the veins filled with foreign minerals, by which the upper 

 strata of the earth in particular are intersected in all 

 directions, derive their origin from similar causes ; that is 



