July 4, 1890.J 



SCIENCE. 



by our instruments near the earth is not remarkable, since the 

 earth and air just above it may neutralize all electric action 

 for a hundred feet or more. Our thunder-storms seem to 

 show an enormous storehouse of electricity at five thousand 

 or six thousand feet above the earth; at least, electricity 

 seems to be concentrated there over thousands of square 

 miles during thunder-storm action. We are taught that 

 electricity forms a sort of dual condition, or the electric field 

 is a double one. May not this electric field draw on the sun 

 for its energy? It is believed that light, heat, and electricity 

 are all different manifestations of the same radiant energy. 

 The abundant source of this energy is the sun. Why may 

 not the sun's electricity, oftentimes observed by its direct 

 effect on our magnetic instruments, and more often still in- 

 directly in our auroras, be intercepted by a peculiar condi- 

 tion of the atmosphere or of the earth below, and thus be 

 concentrated in particular localities? Generally this elec- 

 tricity passes through the air to the earth, but must we think 

 that it always does so? May not this electric field or dual 

 condition gradually develop in the atmosphere largely inde- 

 pendent of the passage of air-particles through wind or con- 

 vection currents? 



The Electric Field. 



For convenience it has been generally considered that 

 particles have a tendency to leave the positive and pass to 

 the negative pole. For example: in the electric arc-light 

 the carbon at the negative pole is built up at the expense of 

 tbe positive. The velocity of transmission of these carbon 

 particles perhaps cannot be determined, but it must be only 

 a very small fraction of that of electricity, 190,000 miles per 

 second. Is there any inherent improbability in the supposi- 

 tion that in this dual condition in the atmosphere there is a 

 tendency for moisture and possibly dust particles, positively 

 electrified, to pass rather rapidly from the positive pole, or, 

 better, positive portion of the electric field, to the negative 

 portion ? We know from observation that during the pas- 

 sage of a high area or clear sky the electric potential, with 

 very few exceptions, becomes markedly positive, while dur- 

 ing the fall of rain it is negative. While a thunder-storm . 

 is passing, there are most violent fl.uctuations of the electrome- 

 ter-needle from negative to positive and back again, as each 

 flash of lightning is noticed. These fluctuations of the nee- 

 dle are perhaps a hundred times as great as under ordinary 

 conditions of rainfall, and take place when the flash is a 

 mile or two away, showing a most extraordinary inductive 

 action upon the atmosphere, and for enormous distances. 

 We have positive evidence of such transmission of moisture- 

 particles by a force entirely distinct from beat, pressure, or 

 any other commonly recognized meteorologic condition. It 

 is known that the moisture in the air is one of the most con- 

 stant elements we have to deal with. The temperature may 

 rise and fall thirty or forty degrees during the day, and yet 

 the quantity of vapor is in no wise changed. The wind, 

 either in direction or velocity, does not change this moisture. 

 The hiding of the sun's heat or light in no wise affects it. 

 Changes in air-pressure produce no effect in general. As a 

 storm approaches, however, we find a most marked increase 

 in this moisture over thousands of square miles, and this even 

 in a calm. As a storm passes ofi', the conditions are sharply 

 reversed. The moisture becomes depleted in a most remark- 



able manner, as though it were actually drawn out of the 

 atmosphere by an invisible agency. 



The most remarkable example of such action was observed 

 on Dec. 22, 1889, from a third-story window of a house in 

 Washington. It will be seen that the conditions were not 

 favorable for observing this effect at its best. At 3.11 p.m. 

 there were 4.09 grains per cubic foot, and for more than twenty- 

 four hours previous there had been an abundance of moist- 

 ure from a storm passing near by. The air was almost a 

 calm, and continued so till nigntfall. At 5.2 p.m., or one 

 hundred and eleven minutes later, there was only 1.04 grain 

 per cubic foot, and this continued as long as observed. To 

 any one who has made determinations of the moisture of the 

 air, and noted its great constancy, frequently for several 

 days, this sudden subtraction must be very extraordinary. 

 If such changes are possible near the earth, and in the cen- 

 tre of a large city with houses for more than a mile on all 

 sides, what may we not expect to take place in the free air, 

 where there are no interferences, and where we know that 

 such forces are acting in far greater intensity than near the 

 earth ? 



Enormous Fall of Rain. 



Just aftfer a thunder-storm or tornado, there are torrents 

 of rain, and in some quarters it is getting to be quite the 

 custom to call such phenomena cloud bursts. In these cloud- 

 bursts almost an incalculable amount of rain falls, more 

 than a foot having been reported at times. In one case four 

 feet of hail were reported. Just how much territory is cov- 

 ered by such a cloud-burst cannot be told, as the data are 

 not sufficiently numerous, but fifty or sixty square miles 

 may be easily considered. We have already seen that the- 

 later theory, which calls for a downrush in the centre of a 

 thunder-storm, effectually disposes of all possibility of this 

 enormous amount of moisture rushing up in the centre and 

 being condensed by expansion. In the case of a tornado, it 

 is incredible that even a thousandth part of this moisture 

 can be carried up in a funnel a few hundred feet in diame- 

 ter. If we inquire what would be the efl'ect of the ordinary 

 condensation of such a mass of water in the air over such a 

 limited space, we are confronted by an amount of heat set 

 free that is simply appalling. One gallon of rainfall gives 

 out sufficient heat to melt forty-five pounds of cast iron. A 

 very little consideration will show us that it is absolutely 

 impossible, even allowing a current of moist air at any con- 

 ceivable velocity, for even a small fraction of rain to be pre- 

 cipitated out of such a current. It has already been shown 

 that the latent heat set free would at once re-evaporate the; 

 moisture. We seem to be driven to invoke the aid of some 

 other agent than any thus far recognized as cogent in pro- 

 ducing our storms. Is it inconceivable that we have to deal 

 here with a negative electric field, which draws to itself with 

 great velocity particles of moisture from regions perhaps for 

 one hundred miles about, when suddenly, upon a discharge 

 of electricity, the potential upon the particles is diminished, 

 and they unite in great abundance and form raindrops? 

 This is a most inviting field for observation. We already 

 have facts enough to make a plausible hypothesis, and, 

 what is very important, we have here an unlimited amount 

 of energy which may be called upon to produce all the ef- 

 fects ever observed. 



