Rotary Action of the Providence Tornado. 



271 



Left or JVorth side of the Track. ! 



Inclination inw'rd and 

 Direction of first backvv'rd fr'm course 

 Case. prostration. of tornado. 



8 S. 11° E. 79 degr's. 



S. 10° E. 80 



CfellS.25W. turn- 

 { edtoS.llE. 



S. SG'^ E. 



S. 55° E. 



S. 55° E. 



first thrown N. 23 

 W. (backward) 



S. 45° E. 



S. 30° E. 



S. 55° E. 



East, 



S. 85° E. 



S. 27° E. 



N.55°W.(backw'rd) 215 



firstfellN.W.turnOgr,^ 

 edtoS.37E. S'^'^^ 



N.45°W.(backw'rd)225 

 C Branch of apple tree ) , qo 

 ^ thrown west j 



S.20°W. (backvv'rd) 110 



S.55°W.(backw'rd)145 



South, 90 



first thrown N.IOW. 260 



9 



10 



11 

 12 

 13 



14 



15 

 16 

 17 



18 

 19 

 20 

 21 



22 



115 



64 

 35 

 35 



247 



45 

 60 

 35 

 

 5 

 63 



23 



24 

 25 

 26 



27 



Case. 



37 



43 



41 



42 



Right or Smith side of the Track, 



Inclination inw'rd and 

 Direction of first backvv'rd fr'in course 

 prostration. of tornado. 



N. 87° E. 13 degr's. 



N. 30° E. 60 



S. 85° E. - 5 



East, 



Mean direction of prostration on the 

 right side of the track N. 73° E. : aver- 

 age inclination inward from course of 

 tornado, seventeen degrees. 



Mean direction of first prostrations on 

 the left side of tracK, S. 4° W. : aver- 

 age inclination inward and backward 

 from course of tornado, ninety four de- 

 grees. 



Relative inclinations of the two sides 

 to the line of axis, more tha.n five to one. 



It is proper to mention, that the average 

 inward inclination of all the prostrations 

 on the right side of the track for a dis- 

 tance of four miles east of the river vvas 

 thirty degrees.* This however does not 

 afljBct the conclusions in favor of rotation 

 to the left. 



These average results, on the two sides, together with the ob- 

 servations already adduced, appear to me to afford decisive evi- 

 dence of whirlwind rotation in this tornado, in the direction from 

 right to left or which is contrary to the hands of a watch. In 

 reference to this evidence and that exhibited in my paper on the 

 New Brunswick tornado, I add from my prepared sketches the 

 following figure, as an approximate illustration of the whirling 

 action in these tornadoes, so far as this may be shown horizon- 

 tally and by a stationary figure. 



Let the involuted hnes or arrows on this figure be supposed to 

 represent the motion of the wind at or near the bottom of a ver- 

 tically cylindrical portion of the center of a tornado, comprising 

 a length of radius equal to the greatest width of the prostrating 

 power on the right of the axis of its path. Now if the tornado 



* This larger average gives a relative degree of inclination on the two sides of 

 three to one. Nearly the same difference is found in two outside bands of prostra- 

 tion, of equal widths, (Tables I and V,) shown in my survey of the New Bruns- 

 wick Tornado. See this Journal, Vol. xli, p. 78. 



