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through the winter of 1901-2; the conclusion is drawn that while the general obscurity of the atmosphere in central London at that season has decreased decidedly during the last half-century, plenty of room for improvement remains. Visibility, Mr. Marshall tells us, still does not exceed 1.25 mile for 80 per cent of the time from November to January.

Section 4 looks into the question of annually recurring warm and cold spells. Here the author uses five-day means of maximum temperature to test the ‘ Buchan periods.’ He reaches a verdict against their reality so far as London is concerned. This discussion, like most of its kind, loses force through ignoring two highly important provisos laid down by Buchan in his original papers of 1867: (a) that ‘ the incidence of each of the periods is subject to variation, and in the case of the December period to great variation, from year to year; ’ (b) that for the detection of these seasonal anomalies ‘ five-day means and such mean tempera- tures as have been “corrected’’ or manipulated in any way are unsuitable.’ How much argument and misapprehension would have been saved had Buchan not been so injudicious as to assign definite dates to

The 39 pages of Section 5 present summaries of temperature and rainfall for each month and year from 1841 to 1949. These refer to Greenwich Observatory until 1870 and to Kew Observatory thereafter, sunshine data being added from 1880 onwards. A prefatory paragraph and table point out the inhomogeneity introduced into the temperature series by the different modes of thermometric exposure - the Airy stand at Greenwich and the north-wall screen at Kew. As compared with the standard Stevenson screen these types of shelter have the effect of expanding and contracting the recorded thermal range respectively. Mr. Marshall shows that over the period 1906-1935 the average difference between the maximum and minimum temperatures was 2.4“F greater at Greenwich than at Kew over the whole year and about 4°F greater from May to August. But these figures are far from evidencing the full extent of the inhomogeneity. A comparison made by the reviewer indicates that from 1871 to 1937 the observed extreme maximum temperature was higher at Greenwich than at Kew by 6°F in 31 months, by 7°F in 19 months, and by 8°F in five months, while the observed extreme minimum was lower at Greenwich than at Kew by 4°F in 31 months, by 5°F in 10 months, and by 6°F in two months. And this despite the fact that Greenwich Observatory is (or was) on a hill-top, whereas Kew Observatory lies near the bottom of a river valley. The apex disparities of 8°F in the maximum readings and 6°F in the minimum readings at these two London stations, a dozen miles apart, represent the normal differences between Penzance and Lerwick and between Torquay and Dundee respectively. Finally, after the index, we have 29 coloured plates setting forth as annual, seasonal and monthly diagrams summaries of the temperature, rainfall and sunshine values detailed in Section 5, plus the day-to-day records of the three elements in individual months that were outstandingly warm and cold, wet and dry, bright and dull. These will have particular appeal to the student of short-term climatic changes.

It could hardly be expected that a work containing such a wealth of statistical material as this would make its first appearance free from factual errors. Perhaps the wonder is that there are not more of them to be pointed out for adjustment in the second edition. The dates 19 October and 16 May given on pp. 27 and 17 for the earliest and latest recorded London snowfalls within the period considered are both incorrect : in 1887 even Kensington had a snow-cover on the morning of 12 October (see British Rainfall for that year), and in 1867 the southern suburbs did not escape the heavy snow-squall in which Hermit won the Derby on 22 May. Also inaccurate is a statement on p. 20 to the effect that no ‘ official ’ ground frosts have come to London in July: Greenwich Observatory had grass minimum temperatures of 28°F on 19 July 1863 and 29°F on 16 July 1919. In the table on p. 91 the coldest May night of 1931 is credited with a screen minimum of 48°F at Kew. This, though copied from the Monthly Weather Report, is obviously wrong, since the mean minimum for the month was 46.9”F; according to the Daily Weather Report 48°F should read 40°F. O n p. 77, 29 April with 13.2 hr is entered as the sunniest day of 1889; 1 June with 13.8 hr should be substituted. O n p. 71, 12 October ought seemingly to be allowed to share with 13 July the distinction of being the wettest day in 1873, and at the bottom of p. 81 there is an erroneous entry for the maximum daily rainfall of 1903. The snowfall of 27 April 1919 is said on p. 15 to have lain 4 in. deep for a time; actually the depth that evening was 8 in. to 10 in. over most of northern and north-western London and reached 12 in. on Hampstead Heath. The table of ‘ absolute droughts ’ on p. 6 covers only the years 1929-49: reference to p. 16 of British Rainfall 1887 and to subsequent volumes of that publication would have enabled the list for Camden Square to be taken back to 1858 with little trouble.

Mr. Marshall adopts a homelier style of writing than is ordinarily found in literature published under the government imprint. Loose syntax abounds. A typical specimen runs (p. 14), ‘ In 1949 the warmest (April) day at Wealdstone was 84°F on the 16th and the coolest night 28°F on the 10th.’ It would be to the advantage of the second edition of the book if all such sentences were amended to read ‘ The warmest day. . , was the nth with x ” F . . .,’ and so on.

periods ’ which on his own showing were inconstant.

E.L.H.

Archiu fur Meteorologie, Geophysik und Bioklimatologie, Serie B, Bd 111. Vienna (Springer), 1951. Pp. 323; Figs., tables. DM.46.

Volume 111, Series B, of the well known ‘ Archiv ’ is dedicated to the General Institute for Meteorology and Geodynamics of Vienna on the occasion of the celebrations in 1951 of the Institute’s centenary. With the Institute in the dedication are linked the names of Prof. Dr. V. Conrad and Prof. Dr. H. Ficker, two of the outstanding meteorologists associated with it in the past 40 years, and who reached their 75th and 70th birthdays respectively in the same year.

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The dedication points out that the receipt of contributions from all over the world for this special number indicates the respect for the scientific work of the Institute and of Profs. Conrad and Ficker.

The volume includes 23 papers from authors in several European countries, the U.S.A. and India. The subjects dealt with include radiation, surface and upper-air climatology, bioclimatology, meteorological effects in disease, evaporation, climatic change, and glaciology.

Only a few papers can be mentioned individually. Albrecht and Goldschmidt each describe observations of total radiation from a cloudless sky and discuss formulae for the relation between the radiation and the altitude of the sun and with cloudiness. Flohn discusses the mechanism of the occurrence of westerly winds near the Equator and Reinhard the upper wind observations made by radar on the continental coast of the English channel during the war. Ramdas gives a valuable survey of the investigations at Poona into the meteorology of the lowest few feet of the atmosphere; this paper contains much information on temperature, humidity and wind gradients, on the heat loss from the surface by convection and on the temperature and humidity in various kinds of crop. Ekhart provides a comprehensive climatological study of 50 years' wind observations at Vienna.

Thornthwaite describes a method of measuring evapotranspiration and some calculations of the potential evapotranspiration for different climates, and Lauscher the worldwide distribution of Hill's cooling power. In one of the papers on meteorological effects in disease Berg produces statistics to show that occurrences of lung embolism are not associated with passage of fronts. Prohaska produces evidence that the Antarctic has not experienced any increase of mean temperature such as has occurred over much of the Arctic since the early years of the present century and Winter examines the secular variations of the summer temperature of Vienna with 25-year overlapping means compiled from the 175-year-long series of observations; the values, dated from the last year of the period, were high in the first thirty and last thirty years of the 19th century, fell after 1900 and are now rising again.

G.A.B.

Archiu fur Meteorologie, Geophysik und Bioklimatologie, Serie A, Bd. IV. Vienna (Springer), 1951. Pp. 448; Figs., tables. DM.65.

Volume IV, Series A, which is also a special number, contains 31 papers, all of them substantial ones, in its 448 pages. Their subjects include tropical cyclones, theory of water-spouts and tornadoes, gravity waves in the atmosphere, lag in radiosondes, solar effects on the frequency of formation of depressions, dynamics of jet streams, formation of ice crystals in the atmosphere, electric conductivity of the air near the ground, electric currents in the ionosphere, changes in ozone amount associated with sudden ionospheric disturbances, methods of statistical and harmonic analysis in geophysics, atmospheric thermodynamics, turbulence, and seismology.

Again only a few papers can be mentioned individually. H. Koschrnieder reviews theories of formation of dust devils and tornadoes and has a detailed analysis with good photographs of a dust devil in process of formation; he regards dust devils as whirls set off as air flows past the edges of obstacles and so accounts for the high proportion of anticyclonically rotating ones and calculates some pressure falls for tornadoes on the basis that the pressure in the centre is at most the same as at the cloud base. W. Bleeker and A. Delver give a new theory of the formation of tornadoes on the basis of the temperature differences between the areas with heavy rain and those without. C.-G. Rossby, in a mathematical paper, explains the formation of jet streams on the basis that stratified air currents assume that distribution of wind velocity with height which corresponds to a minimum value of rate of momentum transfer in the vertical. D. P. McIntyre outlines the main principles of the Chicago school of meteorology and of its leading spirit C.-G. Rossby as devotion to study of the hydrodynamics of the field of flow rather than of pressure. There are two British contributors: Prof. S. Chapman and Dr. R. S. Scorer. Prof. Chapman introduces a new term into ionospheric physics with his equatorial electro-jet ' which is an intense electric current flowing eastwards over the sunlit equator invoked to explain the large diurnal range in the horizontal magnetic force at Huancayo and other equatorial observatories. Dr. Scorer outlines his mathematical theory of gravity-waves in the atmosphere and discusses in detail the circumstances in which the waves can be formed.

May we add our congratulations to the Austrian Central Institute and our best wishes for its second century ?

G.A.B.

Berichte des Deutschen Wetterdienstes in der U.S. Zone, No. 42,1952. Pp. 463; Figs., tables, charts. DM.50.

This number of the series of Berichte of the meteorological service of the U.S. Zone of Germany is dedicated to the well-known climatologist Prof. Dr. K. Knoch on his 70th birthday. The volume contains 107 papers, many very short, in its 463 pages.

The subject range is wide; a rough classification list is clirnatolopy, bioclimatology, micrometeorology, phenology, agricultural meteorology, radiation, instruments, meteorological factors in health and disease, upper air climatology, meteorological organization.

Taking a few papers almost at random: Dr. K. Keil gives an interesting article on the development of the Library of the US. Zone service from its first foundation in 1886 as the Library of the Prussian State