3IO 



SCIENCE. 



[Vol. XV. No. 381 



THE TORNADO : APPEAEANCES ; LIEUT. FINLEY'S 

 VIEWS. 



While it would appear that the most eacoui-aging line of 

 research is in determining the conditions leading up to a 

 tornado, yet thus far the most time has been spent in study- 

 ing the destruction, distribution of debris, violence of the 

 wind, whirling of the clouds, etc., just at the toroado 

 proper, and where investigation would be the most difficult. 

 A tornado appears to be such a definite phenomenon, that it 

 seems at first sight as though the testimony of different 

 observers would be cumulative, and that there ought to be 

 no difficulty in obtaining definite information regarding all 

 its peculiarities. A very short research, however, dispels 

 this view. The reasons for this are so well and concisely 

 given by Dr. Wadsworth, who investigated the tornado oi- 

 April 14, 1879, at Collinsville, 111., that I quote from him. 



" It must be borne in mind that this phenomenon came 

 upon our people without warning, and passed before their 

 vision with a probable speed of more than a mile a minute. 

 The impression thus made would necessarily be far from 

 complete. Of those in or near the path of the tornado, one 

 would observe the lower, aiiother a higher portion, very few 

 noticing just the same features. It. came to some with the 

 shock of an explosion, or, if they were so fortunate as to 

 have it lift as it passed over them, they might see that a 

 lumber-yard was being poured down upon them, which 

 would be equivalent to not seeing the real cause at all, only 

 a secondary result. To others, again, personal preservation 

 was the first law of nature. To those to the north or south, 

 or some distance in advance, and so fortunate as to have 

 their attention properly directed, are we most indebted for 

 what little history we have been able to gather, otherwise 

 than that to be obtained from the study of the destruction it 

 left behind." To this may be added, (1) no two tornadoes 

 ever had the same appearance; (2) in the same tornado the 

 movements are so complex that it is practically impossible to 

 grasp the whole scene; (3) it is believed that it is almost 

 impossible to avoid preconceived opinions, which give an 

 observer a bias one way or another (this is recognized by 

 the most skilled physicists); (4) in many cases leading ques- 

 tions would tend to cloud the truth; (5) it is probable that 

 sometimes a storm not a tornado is mistaken for one, and 

 this serves to confuse the appearances. This was much 

 more of a difficulty forty years ago than now. A good 

 illustration of this (S) may be found in the so-called Natchez 

 tornado. 



Natchez (Mississippi) Tornado. 



This hurricane, for it was undoubtedly a West India 

 cyclone or hurricane, occurred May 7, 1840. Mr. Tooley's 

 description is quoted from. " At 12.45 p.m., the roar of the 

 approaching storm began to be distinctly heard, the wind 

 blowing a gale N. E., 6 (Beaufort). The roar and commo- 

 tion of the storm grew more loud and terrific, attended with 

 incessant coruscations and flashes of forked lightning. As 

 the storm approached nearer, the wind veered to the E., 7. 

 At 1.45 a blackness of darkness overspread the heavens; and 

 when the annulus approached the city, the wind suddenly 

 veered to the S. E., 8, attended with such crashing thunder 

 as shook the solid earth. At 2 the tornado, 10, burst upon 

 the city, attended with such murky darkness, roaring and 



crashing, that the citizens saw not, heard not, knew not, the 

 wide-wasting destruction around them. At this moment the 

 barometer fell to 29.37" (it had been 29.49" at noon). The 

 wind that desolated Natchez was from the S E. A brick 

 house on the north ^side of Main Street had the leeward 

 gable end thrown out, the windward end remaining unin- 

 jured. The windward gable end of a large house adjoining 

 the Commercial Bank bursted outward against the face of 

 the storm; the leeward end was uninjured." It is plain, 

 from the veering of the wind and the steady fall of the 

 barometer, that this storm was not a tornado, and we shall 

 avoid a good deal of difliculty by throwing it out in our 

 studies. 



Two Epochs of Study. 



It is rather remarkable that between the years 1840 and 

 1850 there was most diligent attention paid to this subject by 

 the most noted physicists and meteorologists of that day, — • 

 Joseph Henry, A. D. Bache, Loomis, Espy, Eeid, Redfleld, 

 Hare, and others; and after that period for nearly twenty 

 years, or till the Signal Service was established, there ap- 

 pear to have been very scanty studies of the phenomenon. 

 In some respects this will be an advantage to us, as we can 

 compare the later studies, having all the advantages of 

 weather-maps, concerted action, simultaneous observations, 

 etc., with the meagre data of the earlier explorers in this 

 enchanting field. These appearances have been' so differ- 

 ently described, and there seems to be so much confusion in 

 some cases, that it is best to quote quite freely from the tes- 

 timony of those who were eye-witnesses or personal investi- 

 gators. 



New Brunswick, N.J., June 19, 1835. 



One of the best studied of all tornadoes was this one in 

 New Jersey. I quote from Professors Johnson and Henry. 

 " In a few cases, in which the ridge of a building lay north 

 and south, the eastern slope of roof was observed to be re- 

 moved, or at least stripped of its shingles, while the western 

 slope remained entire. I do not recollect to have encoun- 

 tered a single case in which the top of a tree, with its roots 

 in the ground, was lying towards the west, though I cannot 

 say that none occurred. None were seen with the tops fron 

 the centre of the path. A lad of eight or nine years was 

 carried upward and onward with the wind a distance of 

 several hundred yards, and afterwards descended in safety, 

 being prevented from a violent fall by the upward forces. 

 Rafters which penetrated buildings south of the track, en- 

 tered them on the north side. Their descent, in some in- 

 stances, was with great violence, contrary to what happened 

 in the range of the upward motions, where a lad, already 

 referred to, was deposited in safety after a journey of one- 

 fourth of a mile." Professor Bache also investigated this 

 tornado. He says, " I think it entirely made out that there 

 was a rush of air in all directions at the surface of the ground 

 towards the moving meteor, this rush of air carrying objects 

 with it. The effects all indicate amoving column of rarefied 

 air, without any whirling motion at or near the surface of 

 the earth." 



New Haven, Conn., July 31, 1839. 



A short time before this tornado the wind blew fresh south- 

 east. It changed suddenly south, and in a moment west, 

 where it continued. Professor Olmstead says, " Accompa- 



