ARBORICULTURE 



217 



DOUBLIO LINES OF SNOW FENCES, SOLDIER SLMMIT, UTAH, ON lUO GKANDE WESTEKN 



RAILWAY. 



to such lines. Here the eddy or whirhng 

 removes the pressure from the wheel and 

 also causes the vane to vacillate. 



In the Ohio River opposite the boyhood 

 home of the editor, is an immense sand 

 bar, caused by a projecting ledge of rocks 

 from the limestone hills of the Kentucky 

 shore. In former years this bar ex- 

 tended entirely across the river both 

 above and below the town of Rising Sun, 

 very shallow water covering that por- 

 tion called the channel and steamboats 

 were g-rounded on this bar with fre- 



aoaann 

 aoanDn 



age 



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iv-" 



(•(l\TKOLLI.\"(; FLOW OF WATER. 



quency. Engineers have constructed 

 two (lams projecting from the Indiana 

 shore and one from the Kentucky side, in 

 such manner as to confine the current 

 so that the force of the stream deepens 

 the channel, in order that boats may nav- 

 igate more safely. 



Exactly the same ]:)rinciple governs the 

 wind currents. .\ canyon in the moun- 

 tains diverts the wind, directs its course, 

 and at times increases its velocity. A 

 range of high mriuntains or shar]) hill-; 



deflect it upwards, while belts of trees 

 perform the same service. 



Locomotive engineers inform me that 

 in time of strong head or side winds these 

 have a decided influence upon the train, 

 retarding its progress, and when a belt of 

 timber intervenes the strain upon the 

 engine is relieved and the train shoots 

 ahead with increased velocity. 



The whirlpool phenomenon in the 

 Mississippi River, at Grand Gulf, Aliss., 

 which fiftv years ago was noted as a most 

 extraordinary instance of this reverse cur- 

 rent, and which gave the name to the then 

 important locality, "Grand Gulf," will 

 be recognized by old river men. who 

 knew the place in ante-bellum tunes. 



The river at that time occupied the 

 great bend, which, since the "cut-off" and 

 change in the river bed, has become an 

 inland slough and island. The Big lUack 

 River empties into the Mississippi at this 

 point, while a hard clay point projected 

 from the Louisiana shore. The combina- 

 tion of forces during periods of high 

 water caused this vast pool to whirl vio- 

 lently. Elat boats were often caught in 

 this eddy, and it was with great difficulty 

 thev were gotten out into the regular 

 channel. The writer, in his boyhood, has 

 been in this grand gulf in a skiff, and 

 remembers the efforts he was obliged to 

 put forth to pull his craft out of the 

 whirling waters. This is ui)on the same 

 j)rinciple which we are endeavoring to 

 .'how wlierein the obstacles jilaced in the 



