238 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 19 3 9 



some of these illustrations are of peculiar interest and educational 

 value, because the operation of familiar physical principles in the 

 atmosphere frequently leads to results quite at variance with what 

 is to be expected on the basis of ordinary experience, since, on the 

 scale of atmospheric phenomena, many influences that are negligible 

 in the laboratory become the dominating factors (Humphreys, 1934). 

 Weather phenomena are constantly in evidence, and vitally affect the 

 daily life of everyone ; the immeasurable pleasure to be derived from 

 an abilitj^ to understand and appreciate this familiar element of 

 our physical environment is ample reason for devoting attention to 

 it in the general teaching of physics. 



REFERENCES 

 Bjebknes, J. 



1919. On the structure of moviug cyclones. Geofys. Publ., vol. 1, No. 2. 

 Bjerknes, J., and Solbeeg, H. 



1922. Life cycle of cyclones and the polar front theory of atmospheric circu- 

 lation. Geofys. Publ., vol. 3, No. 1. (Cf. Month. Weather Rev., 

 vol. 47, pp. 90-100, 1919.) 

 Brunt, D. 



1939. Physical and dynamical meteorology, chaps. 2-4. Macmillan Co., New 

 York. 

 Byers, Horace R. 



1937. Synoptic and aeronautical meteorology. McGraw-Hill Co., New York. 



1938. On the thermodynamic interpretation of isentropic charts. Month. 



Weather Rev., vol. 66, pp. 63-68. 

 Humphreys, W. J. 



1929. Physics of the air. 2d ed. McGraw-Hill Co., New York. 



1934. Weather proverbs and paradoxes. 2d ed. Williams & Wilkins, 



Baltimore. 

 Petterssen, Sveebe 



1933. Kinematical and dynamical properties of the field of pressure with 

 application to weather forecasting. Geofys. Publ., vol. 10, No. 2. 

 1936. Contribution to the theory of fr ontogenesis. Ibid., vol. 11, No. 6. 

 Piercte, C. H. 



1938. The use of vertical cross sections in studying isentropic flow. Month. 

 Weather Rev., vol. 66, pp. 263-267. 

 Refsdal, a. 



1935. Das Aerogramm. Met. Zeitschr., vol. 52, pp. 1-5. 

 ROSSBY, C.-G. 



1932. Thermodynamics applied to air mass analysis. Meteorol. Pap. Massa- 

 chusetts Inst. Techn., vol. 1, No. 3. 

 RossBY, C. G., et al. 



1938. Aerological evidence of large-scale mixing in the atmosphere. Trans. 

 Amer. Geophys. Union, 18th Ann. Meeting, pt. 1, pp. 130-136. 

 Weightman, R. H. 



1936. Forecasting from synoptic weather charts. U. S. Dep. Agr. Misc. 



Publ. 236. Washington. 

 1936a. Advances and developments in weather forecasting. Journ. Frank- 

 lin Inst., vol. 222, pp. 527-549. 



