REVIEWS 333 



1891-1910 was Professor of Meteorology in the U.S. Weather Bureau, and since 

 1910 has been in charge of the Argentine Meteorological Office, ascribes this lack 

 of theoretical progress to two reasons. Firstly, that the observations are usually 

 recorded in practical units, and these not in one system only, so that considerable 

 reduction is necessary before they can be used in formulae. Thus, for example, 

 the barometric pressure is expressed usually in inches or millimetres of mercury. 

 Reductions and intercomparisons of observations would be enormously simplified 

 if they were always recorded in one definite system of absolute units, say the cen- 

 timetre-gramme-second-absolute temperature units. The importance of this step 

 to meteorological science cannot be overestimated, and, in thisicountry, Sir Napier 

 Shaw, Director of the Meteorological Office, is striving to secure the general 

 adoption of such a system. 



The second reason advanced by Prof. Bigelow is that theoretical discussion 

 has always proceeded on the assumption that the conditions in the atmosphere 

 are strictly adiabatic, and that the specific heats are constant throughout. A 

 little reflection will show that these conditions are not likely, in general, to be 

 satisfied, and investigation shows that they cannot be as long as there is any 

 circulation or radiation in the atmosphere. The greater portion of this volume 

 consists therefore of the derivation of a system of equations in which the specific 

 heats and gas-constant are not assumed to remain constant (although the ratio of 

 the specific heats does so), and of their applications to the explanation of many 

 meteorological phenomena. The volume thus gives in outline many of Prof. 

 Bigelow's own researches, which have proved very successful in forecasting 

 weather conditions in the United States. 



Prof. Bigelow claims in this way to have given solutions of the following 

 problems, which have not previously been satisfactorily solved : — 



1. The diurnal convection and the semi-diurnal barometric waves, with the 



radiation. 



2. The pressure and temperature in cyclones and anticyclones, with the 



circulation and radiation. 



3. The thermodynamics of the atmosphere from balloon ascents to great 



altitudes. 



4. The thermodynamics of the general circulation. 



5. The distribution of the radiation in all latitudes and altitudes up to 20,000 



metres. 



6. The " solar constant " of radiation and the conflicting results from 



pyrheliometers and bolometers. 



7. The discrepancy in the absolute 'Coefficient of electrical conduction as 



derived from the several apparatus for dissipation and for the number 

 and velocity of the ions. 



8. The diurnal magnetic variations in the lower strata of the atmosphere. 



9. The non-periodic magnetic variations in their relation to the solar 



radiation. 

 10. The magnetisation and electrical terms in the sun at very high temperatures. 



The above ten headings will give some idea of the wide range covered by the 

 book. The treatment is not uniformly good, particularly in the mathematical 

 part. The practice of numbering equations, many of which are merely steps in an 

 argument or transpositions of other equations, consecutively through the book up 

 to a total of almost 800 is wearisome. Also the writing of Cv and Cp instead of 

 Cv and Cp for the specific heats, although perhaps convenient for the printer, is very 

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