March 13, 1902 J 



NATURE 



441 



first place, be remarked that as these cover no less than 

 600 pages, only a very brief reference can be made to each 

 of them. 



The first contribution, by the distinguished late director 

 of the Institute, Hofrath Julius Hann, is a masterly dis- 

 cussion of the meteorological observations made at the 

 Institute during the years 1852-1900. This paper brings 

 together the m.onthly and yearly means of each of the 

 meteorological elements during this period, and in two 

 cases — namely temperature and rainfall — the data given 

 extend back to 1775 and 1845 respectively. Such a long 

 series of temperature observations has enabled him to 

 investigate them for secular variations, with the result 

 that he has found the anomalies to conform to a variation 

 having a period of thirty-five years. It may be of interest 

 here to mention that quite recently Hann has shown 

 {A'ai's. Akad. d. IFi'ss. Jahrg. IQ02, No. i, p. 5) that 

 the rainfalls of Mailand, Padua and Klagenfurt have also 

 a secular variation of thirty-five years, the years of 

 maxima and minima corresponding with Bruckner's 

 epochs. 



Next follow two papers relative to the " Fohn." The 

 first is by Dr. Paul Czermack, in which he describes 

 some experiments that serve to illustrate details in the 

 behaviour and appearance of these currents. The second 

 communication, by Dr. Robert Klein, deals with the 

 daily variation of the meteorological elements at Tragoss 

 due to the occurrence of the '' Nordfohn," and he finds 

 that all the elements are regularly disturbed by it, and 

 offers an explanation for these variations. 



The influence of the " Bora " on the daily period of 

 some of the meteorological elements is discussed by Herr 

 Eduard Mazelle. The observations were made during 

 the years 18S6-1895 at the astro-meteorological observ- 

 atory in Trieste, and the results indicated that the 

 elements changed definitely on these occasions. 



-A. comparatively short paper, by Dr. Victor Conrad, 

 describes the experiments and observations that he has 

 made to investigate the water capacity of clouds and 

 mists. In the first instance he devoted his time to the 

 study of the "aspirationsmethode," producing artificial 

 mists by means of a small boiler. The author then ap- 

 plied this method to natural clouds and mists, making his 

 observations at elevated stations such as Schneeberg, 

 Waxriegel (iS84m.), Schafberg (1798m.), and Hohen 

 Sonnblick (3106m.). The results are a distinct advance 

 on earlier determinations, and, in addition, serve to ex- 

 plain some anomalies previously observed by other 

 workers ; thus, to take one case, the curve illustrating 

 the relation of the water capacity to the " seeing distance" 

 (in the mistj in metres shows clearly the difficulty of 

 measurement of the water capacity when the seeing 

 distance reaches about 150 metres. 



We come now to two papers dealing with the daily 

 variation of the temperatures in Austria and at Vienna 

 (Hohe Warte), by Drs. J. Valentin and StanislavKostlivy 

 respectively. Both these communications are exhaustive 

 investigations on these meteorological elements, but even 

 a brief reference to them must be omitted. 



Dr. J. Pircher is the author of an important memoir on 

 the hair-hygrometer. He first discusses the hair from the 

 point of view of a hygroscopic substance, and describes 

 in detail the features and peculiarities of different hair- 

 hygrometers. This is next followed by a minute experi- 

 mental investigation of the hair-hygrometer and its capa- 

 bility of indicating elticiently the phenomena it is intended 

 to record. Comparisons of the hair-hygrometer with the 

 condensation hygrometer of Alluard, with the psychro- 

 meter, the aspiration psychrometer of Assnian, &ic., are 

 then given, concluding with deductions as to the sensitive- 

 ness of the hair-hygrometer and the influence of the action 

 of direct sunlight upon it. 



Some of the results at which the author has arrived, to 

 put them in a few words, are, that the relative humidity 



NO. 1689, VOL. 65] 



can under all circumstances be measured to within five 

 per cent., but in most cases to three per cent. ; that the 

 efficiency of the instrument is considerably decreased if 

 it be allowed to stand for a long period of time in a room 

 of constant humidity, it being pointed out that it is not 

 only advisable, but necessary, to occasionally moisten 

 the hair ; and, finally, that temperature (with the excep- 

 tion of direct sunlight) and wind velocity have no effect on 

 the instrument, while no variation was observed in the 

 case of pressure. 



A valuable paper by Prof. J. M. Pernter gives the 

 results of some interesting experiments on the polarisation 

 of light in cloudy media and their connection with the 

 present explanation of the blueness of the sky. This 

 investigation was undertaken to answer, if possible, the 

 question whether the light of the sky (Himmelslicht) 

 considered as scattered light of a cloudy medium, and 

 the blue of the sky (Himmelsblau) as the colour of a true 

 medium, could be more easily and, perhaps, also finally 

 answered by the behaviour of light in relation to polarisa- 

 tion than by measurements of the intensity of single 

 colours, since the latter, both with artificial cloudy media 

 and with skylight, are connected with great experi- 

 mental difficulties. Prof Pernter used for the media 

 different percentages of liquids coloured in such a way 

 that he could employ all gradations of colour from the 

 finest blue to a tone of milky white. Through these 

 liquids he allowed rays of different colours to pass, and 

 examined them after transmission by means of a polari- 

 meter. In the summary of the results arrived at it will be 

 seen that an important step in advance has been made 

 from the experimental standpoint, and the observed facts 

 are in harmony with the well-known theory of Lord 

 Rayleigh. 



The last two papers in the volume, which can here 

 only be referred to by their titles, are written by Drs. 

 Max Margules and Wilhelm Traberto, and are on " The 

 Value of Work (Arbeitswert) of a Pressure Distribution 

 and on the Preservation of Pressure Differences'' and 

 " Isotherms of Austria" respectively. In the latter the 

 author has used, whenever possible, the fifty-year means 

 of temperature, and has employed the values obtained 

 from 773 stations in Austria and 142 outlying places ; the 

 maps accompanying the paper illustrate the isotherms for 

 the months of January, April, July and October, the 

 isotherms for the whole year, together with four other 

 maps showing the isotherms for special regions. 



In bringing this necessarily brief digest of the con- 

 tents of this important volume to a conclusion, one can- 

 not but call to mind the very valuable service this Cen- 

 tral Institute of Meteorology has rendered to meteor- 

 ological science in general. The numerous voluminous 

 publications which have issued from its doors, and the 

 very able help it has provided and still provides in many 

 directions, are sufficiently well known to indicate the 

 great activity that is displayed in its various departments. 

 The publication of the volume before us is not only a 

 fitting outcome of such labours, but is a worthy tribute 

 to the memory of those who have striven to place the 

 Institute in the first rank, in which it stands to-day. 



W. J. S. L. 



T//E OWENS COLLEGE JUBILEE. 



ON March 12, 185 1, the Owens College began its 

 existence in a modest house in the centre of 

 Manchester which had formerly been inhabited by 

 Richard Cobden. The College was removed to its 

 present site in Oxford Street in 1873 ; since that date one 

 addition after another has been made to the buildings, 

 which now cover an irregular area of some 240,000 square 

 feet. 



The chemical laboratories have been twice enlarged. 



