• 3iJ 



SCIENCE. 



[Vol. XV. No. 381 



up my mind that there must be a whirl, though in doubt as 

 to its direction. In fact, the best testimony we have, scat- 

 tering of debris, is sti'ongly in favor of the view that there 

 is no whirl. Figs. 3 and 3 will show better than pages of 

 text the nature of this testimony. Let us ask what would be 

 the effect of a whirl, in a direction counter-clockwise, pass- 

 ing through an orchard (see Fig 2). Facing the tornado as 

 it approaches, we would see trees passing our eyes at right 

 angles to the track, or leaning over to the right. After the 

 tornado passes, we would see trees on the south side lying 



^' 



® — 

 « — 1 



PIG. 2. — ORCHAED BLOWN DOWN BY A WHIRL FROM RIGHT 

 TO LEFT. 



parallel to the track, with tops to east, while on the north 

 side their tops would lie to the west. Fig. 3 shows the true 

 conditions which are found. The debris and trees in the 

 centre all lie parallel to the track, while on the north and 

 south sides the trees point inward and forward toward the 

 centre. The writer made a most careful investigation of 

 the conditions at the Wallingford (Connecticut) tornado; 

 and these appearances were repeatedly met with, though the 



FIG. 3. — ORCHARD AFTER ACTUAL TORNADO HAS PASSED. 



true significance of the facts was not fathomed. The stron- 

 gest argument that has been advanced in favor of a whirl 

 has been the position of tall trees which have crossed each 

 other. Almost invariably the under tree is the one pointing 

 north or north-east, while those above point south-east or 

 south. The proof is very unsatisfactory. If there is a 

 steady whirl in a mass of air, why would it not break down 

 neighboring trees in the same direction? 



Further Research. 



We are impressed with the imperfection of the evidence 

 regarding the true mechanism of a tornado. Even the ap- 



parent drawing-up of water from a pond cannot be regarded 

 as evidence of an uprush. We know, that, even if there 

 were a perfect vacuum, water could not possibly be raised 

 more than thirty-four feet. It is probable that the depres- 

 sion noted as the tornado passes is due to the wind, and the 

 apparent rising of a mass of water is simply fine water-par- 

 ticles or mist borne on the wind. The fact of the existence 

 of a whirl is one of the most important that can be estab- 

 lished. While we can never expect that an observer would 

 remain near enough to a very severe tornado to make accu- 

 rate observations, yet it seems as though this fact might be 

 established by skilled observations in a less severe tornado. 

 If you are on the south side of a tornado, there is little use 

 in "looking for a whirl; but attention should be given to- 

 the starting of objects into the air. See whether, when a tree 

 starts, it goes suddenly, as if shot from the ground, or is- 

 swayed violently at the top first; see whether the debris that 

 rises goes up in great confusion, whirling over and over, or 

 whether it is carried lengthwise, as in a stream; etc. If you 

 are on the north side, get as near as you dare, and cling to a 

 large tree, or, better, to a post; note whether a single object 

 near the ground or up in the funnel has any motion what- 

 ever toward your right hand as you look at the funnel. 

 The moment the tornado has passed, run with the greatest 

 possible speed to its rear, and, if possible before the dust has^ 

 enveloped you, see if a single object on the ground or up irt 

 the air is moving to your right. If the tornado has moved 

 through an orchard, establish as near as you can the centre- 

 line, and then pace off one hundred, two hundred, three hun- 

 dred feet to north and south, examine trees at the same dis- 

 tance on either side, and see if those on the south are uprooted 

 or broken more than those on the north. If the tornado is 

 moving at the rate of eighty miles per hour, and the whirl a 

 hundred and twenty, on the south side the resultant velocity 

 would be two hundred, while on the north side it would be 

 only forty miles per hour. The greatest care must be taken 

 that we do not blind our eyes with preconceived notions. 

 When some observer who has a barometer has been so for- 

 tunate as to take it to a dug-out, and has kept his eye upon 

 it rather than upon the more absorbing tornado, we may 

 hope from his testimony, if the funnel goes over his head,, 

 to clear up more doubtful points, and establish more certain- 

 ties, than can ever be done by any other means. Finally,, 

 as the West becomes more thickly loopulated by skilled ob- 

 servers, we may hope to some time establish many points 

 now very uncertain. H. A. Hazen. 



LETTERS TO THE EDITOE. 



*** Correspondents are requested to he as brief as possible. Tlie writer's name 

 is in all cases required as proof of good faith. 



The editor will be glad to publish any queries consonant with the character 

 of the journal. 



On request, twenty copies of the number containing his communication ivili 

 be furnished free to any correspondent. 



To Discuss Meteorological Topics. 



A PRELIMINARY Survey is being made to discover if available 

 material enough exists in and near this city to form a society to 

 study and discuss meteorological topics. Such an organization 

 should include physicians, civil engineers, and other professionals, 

 and amateurs who have studied the weather in a scientific way, 

 or the relations of any of its phases to important human interests, 

 like health, construction of dams, bridges, and buildings, naviga- 

 tion for commerce and pleasure, horse and steam car local traffic. 



