AruiL 8, 1909] 



NA TURE 



167 



superstition connected with " fern seeds," i.e. fern spores, 

 which are supposed to render the bearer invisible. 



A PREMMiN.iRY note by Mr. B. \V. Bazenov, communicated 

 to the Bulletin de I'Academie iinpdriaU das Sciences de 

 St. P^tcrsbourg (series vi., No. i), furnishes a calendar of 

 algal growth in the bay of Sebastopol. Ccramium ruhrum, 

 Cladosiephus verticillatus, species of Callithamnion and 

 Porphyra persist through the year, but start fresh growth 

 in February. The hot-weather algae, e.g. Chondria 

 tcnuissima, Padina pavonia, Dictyota Fasciola, and Arthro- 

 cladia villosa appear in April or May, and persist until 

 August or November. Porphyra leucosticta, Scytosiphon 

 lomeiilaritis, and Ulolhrix implexa show an active period 

 of growth from November to February, and die down in 

 April. Contrasting these periods with the periods for the 

 same algae in the Mediterranean, it is found that the 

 seasonal growth generally begins later and sometimes per- 

 sists longer in the North Sea. 



The prickly pear — a general name for the flat-jointed 

 members of the genus Opuntia — is used as cattle food to an 

 increasing extent in certain of the United States, and in- 

 vestigations into its composition have been made at the 

 New Mexico College of Agriculture. Recently (Bulletin 

 No. 69) the digestibility by steers was determined, and 

 was found to be not unlike that of ordinary green fodders. 

 The results were : — 



It is stated, however, that the digestibility is increased 

 when prickly pear is fed with other foods. 



The Linnean Society has published a very interesting 

 memento of the Darwin-Wallace celebration held on July i 

 pf last year. It will be remembered that an account of 

 the proceedings on that occasion appeared in Nature for 

 July q, 1908. The present volume contains a complete 

 record of the meeting held in the theatre of the Institution 

 of Civil Engineers under the presidency of Dr. D. H. 

 Scott, with full reports of all the speeches then delivered ; 

 a list of those present at the dinner given to the medallists 

 and foreign guests ; the programme of the reception held 

 at the rooms of the Linnean Society, with an account of 

 the exhibits and lantern demonstrations then shown ; the 

 minutes of the meeting held on July i, 1858, and a reprint 

 of the papers by Darwin and Wallace that were read on 

 that famous occasion, together with the joint letter from 

 Lyell and Hooker by which the communications were 

 introduced. Dr. Wallace himself has contributed to the 

 volume an interesting' note, embodying passages from 

 Malthus's " Principles of Population," which illustrate 

 the influence of that work in suggesting the idea of 

 natural selection. Excellent portraits are given of Charles 

 Darwin and of the recipients of the Darwin-Wallace 

 medal, and good reproductions are included of the medal 

 itself and of the beautifully illuminated address presented 

 by the Royal Academy of Science, Stockholm. The whole 

 forms a complete and valuable record of a momentous 

 occasion. 



The National Geographic Magazine for February is 

 largely devoted to papers on western Asia, of which the 

 most important is that by Mr. E. Huntingdon on the 

 mountaineers of the Euphrates. The original population 

 of this region consisted of Kurds, who were conquered by 



NO. 2058, VOL. 80] 



Armenians, and these in their turn by the Turks. The 

 Turks, as a rule, now confine themselves to the richest 

 plains and the cities ; but the areas occupied by the three 

 races are not clearly defined, and when they settle in the 

 same village their quarters are separate. The permanent 

 hostility of these peoples is the cause of the present 

 dangerous political situation. The Kurd hates the Turk 

 because he has been often defeated and is rigorously taxed ; 

 he despises the Armenian because he is a Christian, and 

 can be ill-treated with impunity whenever the Turk gives 

 permission. The Armenian hates and fears both Kurd and 

 Turk. The Kurd, in fact, is a pagan, with an outward 

 veneer of Islam. The Kuzzilbash, or " red-head " Kurds^ of 

 the Dersim district between the two main branches of 

 the Euphrates, are neither good Mohammedans, good 

 Christians, nor good pagans, and another cause of religious 

 animosity is that, being by name of the Shiah sect, they 

 are detested by the Sunni Turks. The illustrations to this 

 paper admirably depict the modes of transit on the 

 Euphrates by means of rafts made of inflated sheepskins. 

 The numerous Hittite inscriptions in this region would 

 attract archseologists if only the new Turkish administra- 

 tion could enforce a semblance of order in this interesting 

 and little-known country. 



The title of a memoir by Mr. Gilbert Walker, F.R.S., 

 on " Correlation in Seasonal Variation of Climate," in 

 vol. XX. o? the Memoirs of the Indian Meteorological 

 Department, is somewhat misleading, as the present part 

 is of an introductory character only, and is confined to a 

 deduction of the correlation coefficient, the regression equa- 

 tions for two or more variables, and the remaining formulae 

 of greatest importance in the theory of correlation, on 

 lines that are for the most part simple. The author pro- 

 ceeds by assuming that the departures of one variable, x, 

 are made up of a portion governed by, and a portion in- 

 dependent of, the second variable, y, and that the portion 

 determined by y may be taken as fey if y be small ; in 

 order to determine a good value of fe, it will be as well 

 to weight each observation equation by the value of its y, 

 as the equations dependent on small values of y are un- 

 trustworthy. It will be seen that this amounts to a way 

 of suggesting the formation of the normal equations of 

 the method of least squares. 



The thirty-first annual report of the Deutsche Seewarte, 

 for 1908, like those of all establishments dealing with- 

 meteorology, shows increased pressure in various direc- 

 tions. In the department of maritime meteorology the 

 chief events have been the publication of monthly pilot 

 charts of the Indian Ocean (see Nature, February 11, 

 p. 443), and the preparation of an atlas of the currents 

 of Indian, eastern Asiatic, and Australian waters. The 

 number of observers in the mercantile marine cooperating-. 

 with the Seewarte at the end of the year was about 1000 ; 

 these receive publications in exchange, and a few medals 

 are awarded annually. In the department of weather 

 telegraphy and storm warnings several improvements 

 have been introduced ; the change of hour from 8h. a.m. 

 to 7h. a.m. at British stations has been of great advantage 

 to the German service. Some 6000 storm-warning tele- 

 grams were issued during the year, but the percentage of 

 success is not stated. Experiments in the use of wireless 

 telegraphy for weather forecasts have been arranged, with 

 the cooperation of the London Meteorological Office. 

 About 200 kite ascents were made during the year, eighty- 

 six of which exceeded an altitude of 2000 metres ; observa- 

 tions with registering balloons have also been regularly 

 made at the times arranged for international ascents. The 



