^8 



NA TURE 



[July 4, 1901 



of Osier's and Dines' anemometers, and the results for each 

 day tabulated. During a very severe gale on December 2S, 1900, 

 the Osier instrument recorded a pressure of 44 '4 pounds on 

 the square foot, the resulting maximum velocity shown by the 

 Dines' anemometer being eighty-two miles. 



M. Arijtowski, of the Belgka Expedition, contributes to 

 Cie! el Terre a note on the climate of glacial periods. Assuming 

 the changes in the level of the snow-line to have been due to 

 changes of temperature only, M. Ar9towski compares its present 

 position at Cape Horn and in South Georgia, and esti mates the 

 corresponding differences of mean temperature, obtaining for a 

 difference of level of 800 to 900 metres a difference of tempera- 

 ture of about 8° C. He urges the special importance of studying 

 the conditions in oceanic climates, and expresses the opinion 

 that the exploration of the Antarctic regions will give the true 

 explanation of the occurrence of glacial periods. 



We have received from the authors a reprint of a paper 

 published in the Memoires of the Belgian Academy of Sciences, 

 by MM. H. Arctowski and A. F. Renard, on the soundings 

 and bottom deposits obtained during the expedition of the 

 Belgica. Although this is a preliminary report, it is not ex- 

 pected that the detailed examination of the deposits, which 

 remains to be completed, will seriously modify the conclusions 

 arrived at. The most important points disclosed by the sound- 

 ings are the existence of a depression of 4040 metres to the 

 south of Staten Island, and of a continental plateau extending 

 south of the 70th parallel. It is noteworthy that the boundary 

 of this plateau is indicated by the isobath of 500 metres rather 

 than by the usual 200 metres. In examining the deposits, 

 the methods employed by Thoulet have been employed in 

 preference to those of Murray and Renard, as the samples are 

 chiefly, terrigenous. The chief interest lies in the obvious ice- 

 berg origin of most of the deposits, indicating the presence of 

 glaciers on continental land to the south and east of the region 

 of the Bilgica's drift. Another feature is the interruption of 

 the zone of diatom ooze in this region. 



A.\ account of the first voyage of the Norwegian fishery 

 steamer, Michael Sars, during the summer of 1900, by Prof. 

 Hjort, is published in the last two numbers of Peleriiianii' s 

 Milleilungen. The paper consists of three distinct parts — (l) 

 oceanographical results, by Bjorn Helland-Hausen ; (2) the 

 distribution of some of the chief forms of Plankton in the Nor- 

 wegian Sea, by Dr. H. H. Gran ; and (3) fishery investigations, 

 by Dr. Hjort. The course of the expedition was from Bergen, 

 across to Iceland, along its north coast to Denmark Strait, 

 thence to Jan Mayen, the Lafotens, Porsanger Fjord, Bear 

 Island, westward to near long. 10' E., and home. The cruise 

 lasted from July to September, and these preliminary results 

 aflbrd important extension and confirmation of the work of 

 the Danish /«^i7^ expedition in the same regions. 



The July Pilot Chart for the North Atlantic and Mediter- 

 ranean, issued by the Meteorological Office, shows graphically 

 the general circulation of the air and of the sea for the month. 

 The region in which gales form as much as 10 per cent, of the 

 wind observations is now limited to the immediate neighbourhood 

 of the southern extremity of Greenland. With the month of 

 July the conditions in the tropics begin to assume a more 

 disturbed appearance, and the seaman consequently finds the 

 letterpress to be largely devoted to a description of West Indian 

 hurricanes and a concise summary of practical rules for hand- 

 ling ships in or near these storms. The path of one of the 

 hurricanes of July 1837 is shown on the chart. As only 355 

 hurricanes h.ave been recorded in 300 years, the annual average 

 is little more than one, but in July 33 were experienced 

 last century, so that one may be expected every three years 

 NO. 1653, VOL. 64] 



in this month. A good deal of information is given on the 

 winds in the Dardanelles. An inset chart gives a thunderstorm 

 type of pressure distribution over western Europe, the remarks 

 stating that there are three distinct classes, (i) those coming 

 from the southward ; (2) those forming locally ; and (3) those 

 appearing as secondaries to depressions in the north. The first 

 of these is the one illustrated. It is interesting to observe how 

 the shading representing fog has been expanding month by 

 month, until in July it extends without a break right across the 

 Atlantic between 40° and 50' N., but it is only about the middle 

 of the Bank of Newfoundland that the frequency amounts to 

 50 per cent. Mariners going up the Labrador coast are in- 

 formed that during the few days of summer the displacement of 

 the horizon by mirage in this neighbourhood occasions great 

 difficulty in obtaining good observations for position. The 

 north-eastward extension of the Gulf Stream drift towards our 

 coasts, which was shown to be interrupted in May and re-estab- 

 lished in June, is again overcome by a general southward flow 

 of the surface water between 10° and 30" W. , the Gulf Stream 

 water apparently not extending northward of the 50th paralle' 

 even on the western side of the ocean. Icebergs have at last 

 appeared about the Kanks, a number having been sighted 

 between April 30 and June i, nearly all clustering about 48° N. 

 48° W., but one in 46° N. 56' W. 



We drew attention in Nature (January 17) to the first 

 number of the Geologisches Centralblatt, which is edited by 

 Prof. Dr. K. Keilhack. We have since received Nos. 2 to 

 10, the last named published on May 15. The total number of 

 works dealt with is 1027, so that our estimate that about 2500 

 will be recorded in the year is probably correct. It is hardly 

 possible to judge of the completeness of the record until the 

 volume for the year is published, but we think that space could 

 be saved by shorter notices of works that are not original 

 articles, such as excursion notes, popular general papers on 

 geology and economic products, text-books, &c. As an 

 illustration of somewhat unequal treatment we observe that the 

 notice of the Suminary of Progress of the Geological Survey of 

 the United Kingdom occupies two pages, and that of the 

 Summary Report of the Geological Survey of Canada only five 

 lines. A valuable feature in the work is the insertion of tables 

 showing new groupings of strata and revised classifications of 

 organic remains. Taken as a whole, it cannot fail to be of 

 permanent service to geologists. 



The University of Nebraska publishes a contribution (No. 5) 

 to the Botanical Survey of Nebraska, conducted by the botanical 

 seminar. The present instalment consists of a number of 

 papers on the general features of the flora rather than of lists 

 of species. 



In the_/««-»a/of the Royal Microscopical Society for April 

 and June are two of Mr. E. M. Nelson's useful papers on the con- 

 struction of the microscope — on tube length and on the working 

 aperture. Mr. Nelson points out that there are no less than 

 three different measurements known as tube lengths, viz. the 

 mechanical tube, the natural optical tube length, and the 

 conventional optical tube length. A table is given of the 

 variations in the lengths of the two different optical tubes for 

 the objectives of various makers and the effect these variations 

 have upon the power. In the second paper Mr. Nelson 

 advocates the importance of distinguishing more accurately than 

 has hitherto been the practice the precise ratio of the diameter 

 of that part of the objective which is utilised to the diameter of 

 the lens itself. 



The report of the experiments superintended by the Depart- 

 ment of Agriculture in Cambridge University has just been 

 issued. The experiments are conducted on various farms in the 



