September 22, 1910] 



NATURE 



Ml 



laid on Scottish examples. Dr. W. F. Hume, in his 

 " Notes on the Petrography of Egypt " {Geol. Mag-, 1908, 

 p. 500) gives a concise sketch that ought to be reprinted 

 for'the use of travellers. Mr. F. Kretschmer (Jahrb. k.k. 

 KeUhsanstalt, Bd. Iviii., p. 527) describes the " Kalk- 

 silikatfelse " near Mahrisch-Schonberg in the Sudetic, and 

 shows them to have become mineralised by the granite 

 of the chain, while (p. 571) certain dyke-like pyroxene- 

 pegmatites have arisen from the absorption of limestone 

 into the invading igneous material. Dr. Hinterlechner 

 and .Mr. C. von John, in an elaborate paper on the 

 eruptive rocks of the Bohemian Eisengebirge {ibid., Bd. 

 lix., p. 127), show that the alteration of the sediments 

 into crystalline schists is not here dependent on the amount 

 of dynamic influence. Where pressure has been least, the 

 crystallisation is most marked, and is due to the intrusion 

 of a mass that was once regarded as a primitive core. 

 This, the earliest granite of the area, is later than Lower 

 Silurian sediments, and Dr. Hinterlechner believes tliat 

 it was intruded after the folding of the district. Since 

 Devonian beds are here involved, this red gneiss may be 

 of L'pper Devonian or Carboniferous age. A paper of this 

 kind emphasises the fact that in true petrology the labora- 

 tory merely subserves the work done in the open field. 



G. .\. J. C. 



REPORTS ON CLIMATES. 



"rHE results of the meteorological observations at the 

 -^ principal stations in the system of the Deutsche 

 Seewarte for the five-year period 1901-5, and for the ten- 

 year period 1896-1905, recently published, complete the 

 series of these valuable statistics for the thirty years 1876- 

 1905. They include the mean monthly, seasonal, and 

 annual values, and extremes or other data relating to the 

 various elements, deduced from observations generally 

 made three times daily, and in practically the same form 

 as in previous instalments. The heights of some of the 

 barometers above sea-level have changed from time to 

 time, but in order to permit easier comparison of one 

 period with another, this inconvenience has been mini- 

 mised by reducing the observations to agree with the levels 

 given in previous publications. Otherwise, as usual in the 

 case of barometrical observations at cliraatological stations, 

 the readings are not reduced to sea-level. 



The meteorology of Peru is discussed by Dr. J. Hann 

 in the Sit:ungsberichte of the Vienna Academy of 

 November 4, 1909. The observations of the various 

 stations on which the discussion is based have been pub- 

 lished in the Annals of the Harvard College Observatory, 

 to which we have previously referred ; the tables were 

 carefully prepared for publication under the direction of 

 Prof. S. J. Bailey, of Arequipa, and are mostly printed 

 in extenso, with mean values, but without discussion. In 

 the present work Dr. Hann has submitted the results of 

 the various elements to minute investigation by the 

 laborious process of harmonic analysis. This brings out 

 many interesting points ; we propose here only to make 

 a few general remarks on the most important station, on 

 the summit of the Mist: (lat. 16° 16' S., long. 71° 25' W.), 

 at the great elevation of 5S50 metres above sea-level. Dr. 

 Hann points out that the agreement of the daily range of 

 the barometer with that of the highest stations in Europe 

 and America is very noteworthy ; the principal maximum 

 occurs between noon and ih. p.m., and the minimum 

 about sh. a.m. The mean annual temperature (1893-5) 

 was —7-8° C; January, — 6-o°; May, June, and August, 

 — 9.7°. The thermometer, even on very fine days, rarely 

 rose above freezing point. Above 4600 metres, only snow 

 or hail was observed ; a certain amount of snow remains 

 during nearly the whole year, but a few clear days suffice 

 to clear off the greater part of a heavy snowfall. 



A valuable paper on the climate of the Lower Guinea 

 coast and hinterland, by Dr. R. Sieglerschmidt, appears 

 in vol. xxiii., part i., of Mitteilungen aus den deutschen 

 Schutzgebieten ; it is the more important from the fact 

 that, with the exception of, a short discussion of the rain- 

 fall of the Cameroons by Fitzner in 1907, no general paper 

 on the climate of that district has been published for some 



NO. 2134, VOL. 84] 



years. Among the earlier papers may be specially men- 

 tioned the results of the Loango expedition (published in 

 1878), observations at Vivi and other places by Freiherr 

 V. Danckelman (1884), and the reports by Lancaster and 

 Meuleman on the climate of the Lower Congo (1897). Dr. 

 -Sieglerschmidt 's article deals exhaustively with each of the 

 meteorological elements, and the general results confirm 

 those given by Dr. Hann in his " Klimatologie," that the 

 air-pressure on the Lower Guinea coast has a single yearly 

 range, and that the yearly means decrease from south to 

 north, while the temperature (reduced to sea-level) increases 

 considerably towards the interior, except in the extreme 

 north. Rainfall increases along the coast from almost 

 complete rainlessness to that of Uie second wettest district 

 of the globe. The oceanic air-current, which from June to 

 September (or October) extends from the north of Angola 

 to the Cameroons far into the interior, has a great in- 

 fluence on the yearly range of temperature, rainfall, &c., 

 while in the hinterland of the north and south districts 

 the yearly range is determined by the alternation of summer 

 warmth and winter cold of higher latitudes. 



The climate of Berlin, part ii., air-temperature, by Prof. 

 G. Hellmann (with the assistance of Messrs. G. v. Eisner 

 and G. Schwalbe), forms part No. 6, vol. iii., of the 

 Abhandlungcn of the Royal Prussian Meteorological 

 Institute. In this valuable and laborious investigation the 

 observations are dealt with in great detail and for various 

 periods from the year 1701. In the following tabfe we 

 quote the maximum and minimum readings for 1830-1907, 

 and the mean monthly and yearly values for 1S22-1907, in 

 centigrade degrees : — 



Jan. Feb. March April May June 



Mean max. ... 14 3-3 7-0 12-9 18-5 22'5. 

 Mean min. ... -32 -2-0 0'2 4-3 8-8 12-8 



True mean ... -fi 0-5 3^4 8-6 13-6 17-5 



July August Sept. Oct. Nov. Dec. 



Mean max. ... 23-8 22-8 I9'0 I2'9 6-3 2-7 



Mean min. ... 14-3 I3'9 10-5 64 i '6 -1'4 



True mean ... 189 i8"l 146 9'5 39 07 



Yearly mean, 9-0; absolute maximum, 37-0 (July 20, 

 1865); absolute minimum, —25.0 (January 29, 1830, 

 January 22, 1S50). 



The author points out that the earlier period was some- 

 what colder than the later ; this was noticeable in all the 

 winter months, especially in January, while greater heat in 

 summer, especially in May and August, was observed, but 

 he considers that it would be premature to assume that a 

 permanent change of climate has taken place. The prin- 

 cipal anomalies in the yearly range are the cold periods 

 in the middle of February and June, and the warm periods 

 near the end of September and middle of December. The 

 cold spell of May 11-13, popularly known as the days of 

 the Ice Saints, is not specially noticeable. The chief cause 

 of these anomalies in the annual range of temperature is 

 the distribution of air-pressure in Eurasia, especially the 

 position of the barometric maximum. 



A comprehensive discussion of the rainfall of northern 

 Spain and Portugal, by Dr. W. Semmelhack, is contained' 

 in Aus dem Archiv der Deutschen Seewarte (1910, No. 2). 

 It deals with many aspects of the subject, including hori- 

 zontal and vertical distribution of amount and frequency, 

 isohyets and tabular means of years and seasons, thunder- 

 storms, &c., embracing a period extending from 1S61 to 1900. 

 The rainfall is affected chiefly by conditions of pressure 

 over the Atlantic, Mediterranean, and the Continent, and 

 its yearly distribution is therefore subject to considerable 

 fluctuation. To give details would require much space, 

 but a rough idea may be gained from the fact that about 

 4 per cent, of the area in question receives an amount 

 not exceeding 12 inches; 53 per cent., approximately 

 12-275 inches; 17 per cent., 274-39! inches; 23 per cent., 

 39J-59 inches; 3 per cent., more than this amount. The 

 extreme values are 9'6 inches at Palencia (Old Castile) 

 and 113 inches at Sierra d'Estrella. The monthly extreme 

 values vary very greatly ; the highest are met with on the 

 N., N.W"., and W. coasts. In March, 18S6, 487 inches 

 were recorded at Sierra d'Estrella, but in the dry districts 

 of the central plateau the greatest monthly amounts are 

 little above 6 inches ; rainless months occur at times at 

 nearly all the stations. 



