>[see reference (18)]. 



egg Tables 751 and 752 



TABLE 751. — Thunderstorm Electricity 



Quantity discharged by a lightning flash: io to 50 coulombs; 



average 20 coulombs. 

 Energy of a lightning flash : 10" ergs. 

 Potential difference between discharge points : 10* volts. 

 Potential gradient at earth's surface beneath a thundercloud: io 4 



volts/meter. 



(The charge producing this field more frequently negative than 

 positive). 

 Number of lightning discharges over entire earth each second : At 



least 100. 

 Duration of lightning flash: More than 0.001 sec [see reference (19)]. 



TABLE 752. — Charge on Rain and Snow 



Specific net charge on precipitation : 



Average, 0.5 c.g.s.e./gm. 1 . , . . . 



\r • u a 1 K see reference (3)]. 



Maximum observed, 20 c.g.s.e./gm. J 



Specific charge on individual raindrops or snowflakes : 



Rain, + 2.7 to — 3.2 c.g.s.e./gm.^ 



Snow, +ii.6to-8.ic.g.s.e./gm.| [seereference ( 20 ^ 



References 



(1) Res. Dep. Terr. Mag., 5, 361-424, 1926. (2) Res. Dep. Terr. Mag., 6, 425-460, 1927. 

 (3) Miiller-Pouillet, Lehrb. Phys., 5, Halfte 1, 11. Aufl., 1927. (4) H. Norinder, Vet.- 

 Ak. Handl., 58, No. 4, 1918. (5) Mauchley, S. J., Terr. Mag., 28, 61-81, 1923. (6) Hess, 

 V. F., The electrical conductivity of the atmosphere and its causes. Translation by L. W. 

 Codd, 1928. (7) Wigand, A., Ann. Phys., 66, 81-109, 19-21. (8) Hess, V. F., Beitr.- 

 Geophys., 22, 256-314, 1929. (9) Geiger-Scheel, Handb. Phys., 14, 1927. (10) Wigand, A., 

 Phys. Zs., 22, 36-46, 1921. (11) Schuster, A., Manchester, Mem. Lit. Philos. Soc, 48, 

 no. 12, 1904. (12) Nolan, J. J., Boylan, R. K., and de Sachy, G. P., Proc. Roy. Irish 

 Acad., 37, A, 1-12, 1925. (13) Nolan, P. J., and O'Brolchain, C, Proc. Roy. Irish Acad., 

 38, A, 40-48, 1929. (14) Gockel, A., Neue Denkschr. Schweiz. Naturf. Ges., 54, Abh. 1, 

 I 9 I 7- 05) Wait, G. R., Carnegie Inst. Washington, Year Book, No. 28, 274-275, 1929. 

 (16) Aitken, J., Collected Scientific Papers, Cambridge, 1923. (17) Wigand, A., Ann. 

 Phys., 59, 689-742, 1919. (18) Wilson, C. T. R., Journ. Franklin Inst., 208, 1-12, 1929. 

 (19) Appleton, E. V., Watson Watt, R. A., and Herd, J. F., Proc. Roy. Soc. (A), in, 

 6i5-(>77, I9 2 6. (20) Schwend, P. G., Jahrb. Radioak., 17, 62-79, 1921 ; Beilage, Jahresber. 

 d. Kantonalen Lehranstalt, Sarnen, 1921-1922, 1922. (21) International Critical Tables, 

 6, 442-445, 1929- 



For current literature consult Journal of Terrestrial Magnetism and Atmospheric 

 Electricity, Baltimore (vol. 38 in progress 1933), and Zeitschrift fur Geophysik, Braun- 

 schweig. 



Smithsonian Tables 



