148 



OCEAN ATMOSPHERIC-ELECTRIC RESULTS 



Table 3. Valuesof atmospheric-electric elements during fog, mist, and haze, June 2-July 21, 1929; derived 

 fair-weather current-density values based on assumed heights of regions containing the fog, mist, or haze 



current density average about 1.4 x 10-7 esu lower than 

 the April to July values, throughout the latitude range. 



Accepting the curve for April to July data shown in 

 figure 15, the air-earth current density for group 3a is 

 too low by the amount of 4.4 x 10-7 esu, for group 3b it 

 is too low by 3.6 x 10-7 esu, and for group 3c it is only 

 0.4 X 10-7 esu too low. If, now, one wishes to examine 

 into the mechanism which is causing too low values of 

 current density, the method employed by Wait (5) in his 

 study of changes in the columnar resistance of the at- 

 mosphere over the Watheroo Magnetic Observatory in 

 Western Australia, provides some interesting informa- 

 tion. In this method the columnar resistance of the at- 

 mosphere is thought of as consisting of an upper and low- 

 er part, with the resistance of the upper part remaining 

 unchanged even on those occasions when the resistance 

 of the lower part is altered considerably by the intro- 

 duction of mist, fog, or haze particles. Measurements 



of potential-gradient and conductivity in the lower part 

 during the periods of fog, mist, or haze, used in conjunc- 

 tion with other measurements accepted as typical of con- 

 ditions prevailing when the disturbing effects are absent, 

 permit one to deduce a height for the lower disturbed 

 region, assuming always a uniform vertical distribution 

 of the medium in that height. 



One must note at this point a difference between the 

 present data and those utilized by Wait. In his paper, 

 the data included observed ocean values of i^ and si- 

 multaneously observed values of iu for the Watheroo 

 Observatory, from which he obtained the height, hu, of 

 the disturbed lower region of the atmosphere at Watheroo. 

 For the present paper, since only ocean data are being 

 considered, only values of iu, and not simultaneous val- 

 ues of in and iu, are available for any disturbed period. 

 Under these circumstances both in and hu are unknown, 

 and one may assume certain values for either one and 



