576 



NATURE 



[February 29, 1912 



While Abercromby's view of cyclones still explains 

 most of the appearances, Dr. Shaw is careful to point 

 out that the old simple conception of the cyclone as 

 a whirl of air inwards and upwards is not the only 

 one possible, and that similar results would be yielded 

 if the air in any part of the system performed no 

 considerable portion of a complete revolution. 



The next three chapters, on the physical processes 

 of weather, the life-history of surface air-currents, and 

 the minor fluctuations of pressure, are the most im- 

 portant in the book, for they are the embodiment of 

 the researches made by the author and his assistants, 

 and they are written with the freshness and convic- 

 tion only possible when the facts dealt with have been 

 won from the unknown by the narrator himself. 

 Were one inclined to be critical one might perhaps 

 hint that more space than is necessary for an account 

 of weather forecasts is taken up by the curious 

 paradox of cooling by warming, and the quantita- 

 tively insignificant condensation by mixing of air of 

 different humidity. Such a criticism, if made, would 

 probably be" wrong, for it is precisely such cases which 

 give force to the demonstrations of the great thermo- 

 dynamical principles still imperfectly grasped by many 

 meteorologists, though held as " fundamentals " from 

 their youth up by the pupils of such men as Kelvin 

 and Tait. Dr. Shaw is at his very best when un- 

 ravelling the tangled skein of air-trajectories in the 

 path of an advancing cyclone, and it is only when 

 he comes to these chapters that a student unfamiliar 

 with the papers in which the various researches were 

 published can realise to the full how tenderly the 

 author in the new light of his personal researches, 

 which now appear for the first time in a text-book, 

 has dealt with the prepossessions of the holder of 

 the revolving-wheel theory of cyclones. 



The old meteorologist must purge his sight of the 

 image of the " revolving storm " if he is to understand 

 what is, after all, the simpler statement of the onward 

 sweep of vast air-streams on the margins or in the 

 heart of which the various " disturbances " occur. 

 Dr. Shaw proves to demonstration that we must view 

 the normal condition of air as one of motion, not 

 of rest, and that the temperate cyclones are disturb- 

 ances of pressure carried along in the stream, not 

 independent forms moving through normally still air. 

 He shows also, as Hellmann in particular has dci.e 

 in his recent work on the Oder floods, that the isobars 

 of a cyclone are not the simple flowing curves of the 

 weather charts, but when mapped in greater detail, 

 for smaller intervals of pressure, and from more 

 stations of observation, they show a variety of 

 "embroidery," as he happily puts it, and in that 

 embroidery resides the explanation of most of the 

 anomalies of the traditional cyclonic convention. We 

 may perhaps be pardoned for hinting that some per- 

 tinent examples of the relation of rainfall to isobars 

 might have been obtained if the maps of heavy rains 

 in the pages of "British Rainfall" had been drawn 

 upon ; they are at any rate the most detailed instances 

 of the mapping of precipitation. We are also a little 

 sorry that the French terms, Ugne de grain and rtiban 

 de grain are not translated and brought into intimate 

 NO. 2209, VOL. 88] 



relation with the English line-squalls, the fine tr<- 

 ment of which is one of the best points of the disci 

 sion of the "embroidery," though were we to sami ^ 

 all the good points we might run some risk of -,'. 

 encounter with the law of copyright. 



The remaining chapters, with one exception, d' 

 with practical matters of forecasting as carried ( 

 in the London office. Important as they are, tht - 

 do not carry the same load of scientific interest .1- 

 the earlier portion, in which we see the rebuilding 

 meteorological theory as a house is rebuilt by \'. 

 successive destruction and reconstruction of part- 

 The exceptional chapter is that on anticyclon> - 

 which is all new and of the utmost value. But 1 

 its name, which is apparently honoured for the sal^- 

 of its godfather, the anticyclone would, we fear, be 

 cast down from its high place, and proved to be a very 

 ill-carved fetish. The beneficent purveyor of fine 

 weather, the promoter of brilliant summer warmth 

 and glorious winter cold is, in fact, shown up as an 

 isobaric fraud. The anticyclone is now declared not 

 to be a region of dry, descending air, not to be a 

 focus of winter cold, not to be the country of origin 

 of outward-moving air-currents, not even to be a 

 distinctive meteorological entity. Quoting from his 

 " Life History of Surface Air Currents," Dr. Shaw 

 says : — 



" Further evidence in favour of regarding anti- 

 cyclones as masses of air which for some reason is 

 not taking part in the circulation going on around it 

 may be derived from the study of anticyclones them- 

 selves. They are not of single meteorological char- 

 acter. Local changes of many kinds may take place 

 within them, and almost any kind of weather, except 

 those which represent violent atmospheric changes, 

 may be associated with their central regions." 



A chapter on " Forecasts for Aeronauts " gives 

 occasion for a concise account of the present state of 

 our knowledge of the upper air. Brief reference is 

 made to statistical methods for long period and 

 seasonal forecasting, in which various periodical rela- 

 tionships are touched upon, though lightly, and the 

 book concludes with a discussion of the practical 

 utility of weather forecasts, written in an impartial 

 and eminently scientific spirit. In this respect a 

 strong point is made of the necessity of trained intelli- 

 gence and some knowledge of meteorology on the 

 part of the public in order to fit them to understand 

 and test the forecasts as issued in the Press. Until 

 some such educational groundwork is laid, Dr. Shaw 

 thinks that we cannot be said to have a system of 

 forecasting, for the work of the office is only half 

 the story. As to the possibility of future improve- 

 ments, he says : — 



■' It is quite possible that the progress of research, 

 guided primarily by the wish to improve the daily 

 forecast, will lead to the recognition of, or find mate- 

 rial for, the development of laws of a more general 

 character that will enable us to anticipate the weather 

 for the season or the month. It is only by close 

 practical study that such an object can be achieved." 



The example set by the director will, we are sure, 

 be followed by the band of trained disciples he has 

 gathered round him at the Meteorological Office, and 



