8o 



NA TURE 



[May 23, 1901 



At Singapore the eclipse was very well seen, totality 

 occurring about 12.51 p.m. An interesting series of 

 observations of the temperature variations were made 

 there. The reading before eclipse in full sun was 143', 

 which fell during totality to 81", which was 2 degrees 

 below the normal shade temperature. 



RECENT WORK OF THE U.S. WEATHER 

 IWREAU.^ 



T"" HE Report of the Weather Bureau for the year ended 

 ■•- June 30, 1899, which appeared at the end of last 

 year, extends over two volumes. The first, which in- 

 cludes the usual administrative report and the climato- 

 logical statistics of the United .States Weather Service, 

 is a volume of the ordinary dimensions, while the second 

 and special volume, being part vi. of the whole report, 

 is devoted to Prof, liigelow's discussion of the United 

 States' contribution to the international cloud observa- 

 tions. It is a bulky volume of no less than 787 Cjuarto 

 pages. 



Glancing at the first volume, attention is turned natur- 

 ally to those points in which the practice of the United 

 States Weather Office differs from that adopted in this 

 country, and the first point to be noticed is that from 

 March 1899 the period covered by the night forecasts 

 was increased to forty-eight hours, and that the e.\tension 

 of period has worked successfully, whereas the limit of 

 the British forecasts is twenty-four hours. It is true that 

 the British Isles occupy a remarkably difficult position 

 on a weather map. They are not only at the extreme 

 west of Europe and catch the first effects of weather 

 changes travelling eastward, but they are in a special 

 manner the battle-field of the elements and are vexed 

 with all the storms that belong to so-called temperate 

 latitudes and western shores. These adverse circum- 

 stances in a British mind should provoke more daring 

 enterprise rather than complacency with partial successes, 

 yet we are still without telegraphic reports from Iceland, 

 a recognised centre of atmospheric influence, and wireless 

 telegraphy has not yet extended westward the available 

 area of information. 



The weather service in the United States is indeed a 

 popular one. From a table in the report it appears that 

 the total number of addresses in the United States sup- 

 plied with forecasts and special warnings reached the 

 astonishing figures of 24,467,106. With these no British 

 statistics can be compared. 



It would require too much space to enter into details of 

 the climatological data, 'which include, amongst other 

 things, means of hourly readings at 28 stations It should, 

 however, be remarked that the year under review was note- 

 worthy for the establishment of a number of stations for 

 the storm-warning service in the West Indies at the con- 

 clusion of the war with Spain, and for the extensive 

 system of aerial investigation by means of kites at 17 

 stations. This work was continued until the middle of 

 November, 1S98, by which time 12 17 ascensions of 1000 

 feet and above had been made. 



The second volume, written by Prof. F. H. Bigelow, is 

 devoted exclusively to the cloud observations made in 

 accordance with international agreement between May i, 

 1896, and July i, 1897. It is a very interesting and 

 valuable contribution to the study of meteorology by 

 observation of clouds, and the discussion is very fully 

 carried out. The observations were of two kinds — theo- 

 dolite observations at Washington, by which observers 

 could determine the actual heights and velocities of 

 individual clouds, and nephoscope observations at 15 

 stations in the United .States from which velocities were 

 estimated by the somewhat precarious method of assum- 



re. Re]ort of ihe Chief of the 



NO. 1647, VOL. 64] 



ing the height of the particular type of cloud observed. 

 The theodolite observations are printed in columns 

 arranged according to the type of cloud observed, and 

 occupy 93 pages of the volume. Their discussion leads 

 directly to some very interesting results as to the 

 variation of the velocities of clouds with height. 



The nephoscope observations numbered some 23,000. 

 In order to coordmate them the whole United States area 

 is first divided into six districts, and the position of each 

 station for each observation with regard to a centre of 

 high or low atmospheric pressure is identified by assigning 

 it to one of twenty subsidiary areas within a circle of 1500 

 kilometres surrounding the centre of high or low pressure, 

 as the case may be. In this way the distribution of 

 velocity round the centres of " high " and " low " areas for 

 each cloud level can be set out and the gradual change in 

 distribution from the surface wind to the regular easterly 

 march of the cirrus at about 10 kilometres height is traced. 



In further discussion of the velocities at the different 

 cloud levels, the general easterly drift at different levels is 

 allowed for, and the residual vectors of velocity are' 

 plotted in diagrams to show tlie circulation components 

 in "highs" and "lows" at the different cloud levels. 



The same data enable the barometric gradients to be 

 calculated, and the interesting results follow that the cir- 

 culation phenomena are most vigorous in the middle 

 group of cloud levels, viz. the Strato cumulus to Alto- 

 stratus group, and that there is no experimental evidence 

 to show that there is an overflow of air from the upper 

 part of a cyclonic area causing a higher pressure around 

 it, as has been generally assumed. 



The application of these results to the several districts 

 of the United .States in different typical states of weather 

 is represented in 66 maps of the movement of the air 

 at different levels over the United States. This completes 

 the primary reduction of the observations. The remainder 

 of the volume is occupied with the application of the 

 inductive results obtained. First a section is devoted to 

 the diurnal variation of the barometer. The diurnal 

 variation of winds (taken from European stations) and of 

 cloud motions at the alto cumulus, cirro cumulus and 

 cirrus levels, taken from the cloud observations, is com- 

 pared with the diurnal variation of magnetic force as part 

 of a discussion of a possible relation between diurnal 

 variation of barometric pressure and magnetic force. 

 Without expressing an opinion upon Prof. Bigelow's own 

 views, which have given rise to some controversy, it may 

 be said that this discussion is very suggestive in view of 

 the ideas which have recently been developed from Prof. 

 Thomson's suggestion of " bodies smaller than atoms," 

 Arrhenius and others, of the possible reception of parti- 

 cles from the sun carrying electrical charges which can 

 move with the upper atmosphere. 



Prof. Bigelow next deals with the general theory of 

 atmospheric circulation in relation to the light thrown 

 ujjon the subject by the cloud observations. He com- 

 mences the discussion by a general review of his malhe- 

 matico-meteorological troops. .All the numerical, thermo- 

 dynamical and hydrodynamical formuki; available for 

 meteorological warfare are paraded for inspection by the 

 reader, and they are clothed in a new uniform on account 

 of the need for a standard system of notation for meteor- 

 ology. The uniform does not always C|uite fit. " Pounds 

 X (foot)-" seems to require some sort of inversion before 

 it can appropriately clothe pressure. But that is a small 

 matter. The array of formuke is very imposing, not to 

 say repellent, and this part of meteorology needs a uniform 

 that is less oppressive for the civilian meteorologist. But 

 Prof. Bigelow's investigation moves generally upon sound 

 lines. His criticism of Ferrel's solution of the problem of 

 the local cyclone is sound, and his diagram (chart 69" 

 representing the alternation of high and low areas as 

 resulting from the play of pressure due to the action of 

 two opposing streams of air is a very useful representa- 



