SCIENCE. 



[Vol. XVI. No. 387 



tainly dealing here with a plenum which moves with the 

 storm, and in fact is the storm itself. It may not be that 

 this is due to a downrush of air-particles from some height; 

 but there is no serious difficulty in assuming that, through 

 electrical action, there is an increased pressure in the centre. 

 It is plain that the foregoing description has a most marked 

 parallelism with that already given of the tornado, and it is 

 virtually admitted that a tornado is simply an extreme de- 

 velopment of a thunder-storm. 



The attempt to show that while these phenomena are alike 

 in most respects, and yet that in one of the more important 

 factors they are entirely distinct, is most remarkable. We 

 are taught that the origin of both is an unstable equilibrium, 

 in both there is an uprush of air, in both there is a cloud of 

 dust, in both there appear to be two clouds meeting from 

 the north-west and south-west, in both there is a loud roar 

 heard oftentimes, and in both there is a pronounced cooling. 

 They are exactly alike, and produced the same way, but the 

 final result of these actions is to develop two entirely dis- 

 similar and almost opposite conditions. We are told that in 

 a thunder-storm the air starts upward in the centre, has its 

 moisture condensed by expansion, and the resulting precipi- 

 tation cools the air, increases its density, and finally the di- 

 minished pressure at starting gives way to an increased 

 pressure from this change in the density. It must be ad- 

 mitted that this is a reasonable conception, and may be true; 

 but would not this at once destroy the ascending current, 

 and bring the whole action to a standstill? Can we for a 

 moment have both uprushing currents in a storm-centre feed- 

 ingitsenergy, side by side with downrushing currents increas- 

 ing the pressure? It is only necessary to state this contradiction 

 in order to show the absurdity of the hypothesis. This theory 

 strikes at the root of the whole process of liberation of energy 

 in a moist ascending current; but, more than that, if there is 

 such a cooling and subsequent downrush, why should it not 

 act in precisely the same manner in a tornado? How is it 

 possible for this same uprushing current, which starts in 

 exactly the same way in both these conditions, to continue 

 upward in a tornado, to gather energy as it rises, to liberate 

 more and more latent heat, to rush faster and faster, to grow 

 warmer and warmer, and finally to produce the violent tor- 

 nado with its supposed almost perfect vacuum in the centre, 

 where a half-mile away there is perhaps a thunder-storm 

 causing an increase of pressure? It would seem as though 

 there could hardly be a plainer exposition of the utter futil- 

 ity of all the attempts that modern theorists have made to 

 grapple with this problem than this latest attempt to start 

 the thunder-storm and tornado in the same direction, and 

 finally bring them out, from almost the same conditions, 

 facing in opposite directions, and absolutely dissimilar in 

 their most essential characteristic. 



Explosive Effects. 



Is it possible for electricity to produce a sudden increase 

 of pressure in a mass of air sufficient to violently rend asun- 

 der objects which it strikes? Oftentimes the bark of trees 

 has been driven off; and the usual explanation of this has 

 been, that the heat of the electricity has converted the sap 

 into steam, and this in turn has forced off the bark. This, 

 however, is not satisfactory, for the reason that even a dead 

 and perfectly dry tree has been struck, and scattered over a 



large fi^eld. A remarkable instance of explosive action in a 

 lightning discharge is to be found in Nature for May 8, 

 1890. A tree standing in a rather open field was struck by 

 lightning, and its fragments strewed over two acres of 

 ground. One solid piece weighing five pounds and a half 

 was thrown three hundred and seventy-eight feet. Other 

 debris lay two hundred and ten feet in another direction. 

 Small pieces of riven trunk and bark were found thrown in 

 the teeth of the wind and one hundred and eighty feet from 

 the tree. The concussion or increase of pressure smashed six 

 fine glass window-panes in a house not far away. Another 

 very interesting effect was noted in a house that was struck in 

 Washington, DC., Aug. 23. 1885. In this case the lightning 

 struck the south-west corner of the tin roof on an ell built on 

 the south side of the house, and divided. A portion of the fiash 

 passed down an eaves-spout; and at its end, v?hich was two 

 or three feet above the ground, it passed through the air to 

 the damp side of the house, knocking off the plastering on 

 the inside The other portion of the flash passed down be- 

 tween the weather-boarding and the plastering on the east 

 sid% shattered one of the upright posts, and appeared to 

 explode off the weather-boarding toward the east, and the 

 plastering toward the west. A woman and her two sons 

 were apparently stunned by the effects. 



While such cases have usually been regarded as "freaks" 

 of lightning, yet it would seem that the matter has not been 

 sufficiently studied to enable us to determine just what effect 

 such, a discharge would have upon a confined air space. It 

 may be, the apparent bursting of a house in a tornado may 

 be accounted for in this way. An instance has already been 

 given at St. Louis of a rise in pressure, as shown by a baro- 

 graph, and at the same time a seeming bursting of houses. 

 Hardly a month passes that there is not some discovery re- 

 garding this extraordinary force of electricity, and surely 

 we are not in a position to deny that it might not produce a 

 large number of effects now observed in a tornado, such as 

 searing of green leaves, discoloring the trunks of trees, in- 

 creasing the pressure, exploding houses, depluming fowls, 

 etc. We are told that lightning-fl^ashes are seldom seen in 

 a funnel-cloud. They have been seen there many times. 

 Moreover, it is not at all certain that an ordinary observer 

 would be in a condition to take particular notice of the pres- 

 ence of electricity in a tornado; and, again, the electricity 

 may pass down or up the funnel without a visible flash. 

 The presence of ozone has been often noticed in a tornado 

 where no lightning was seen. 



Possibilities of Electric Action. 



It has been my purpose for many years to avoid, as much 

 as possible, all speculations in considering air motions and 

 the causes of atmospheric phenomena. This is especially 

 pertinent when we consider electric action in the atmos- 

 phere. It is very difficult to believe that electricity has 

 nothing to do with our thunder-storms, and is merely a re- 

 sult, and never a cause. The fact that physicists have never 

 yet been able to account for more than the smallest fraction 

 of atmospheric electricity should lead us to greater diligence 

 in determining its methods. We know from observation 

 that the electric potential is enormously increased as we as- 

 cend in the atmosphere. That little or no connection be- 

 tween atmospheric electricity and storms has been observed 



