52 EFFECTS OF WINDS AND OF 



far to the southeastward of the Strait of Mackinac. It has no detached 

 bay portions worthy of note. For north winds and south winds the nodal 

 line consists of three short detached portions, one near the extreme southern 

 end of Lake Michigan, one across Saginaw Bay, and one in the extreme 

 southern end of Lake Huron, near Port Huron. Note the range horizontally 

 through which the nodal line shifts when the wind changes from northwest 

 to north and again when it changes from north to northeast. 



There are some other very short detached bay portions of the nodal lines 

 on Lake Michigan-Huron, but they are of local importance only. They 

 can not be shown on the scale of plates 5 and 6. 



To apply formula (59) to a particular gage, the Buffalo gage for example, 

 let it be rewritten thus: 



H b = Ci2 b (65) 



in which the subscripts 6 stand for the Buffalo gage, and S& is the S-- of 



D 3 



formula (59) from the nodal line to the Buffalo gage. The value of S& may 

 be obtained easily from such a computation as that illustrated in table No. 



9 by merely taking the difference between 2 at the nodal line, of which 



D 3 



the value is determined from this computation as already indicated, and the 



value of S at the Buffalo gage which is shown directly in the computa- 

 D 3 



tion. 



Formula (65) is of the proper form for application to any gage on any 

 lake by merely changing the subscript and making the corresponding changes 

 in interpretation. 



The values of the S of such an equation as (65) will in general be different 

 for each gage and for each direction of wind over the lake. 



VALUES OF 2x. 



The various values of S x have been computed, in the manner indicated on 

 pages 44-52, for the five gages at Buffalo, Cleveland, Milwaukee, Harbor 

 Beach, and Mackinaw. The values are shown in table No. 10, which follows, 

 in the units indicated in connection with tables Nos. 8 and 9. 



There are certain features in table No. 10 which it is desirable to note in 

 the attempt to secure definite and correct ideas as to the wind effects on the 

 two lakes under consideration. Attention is called to some of these in the 

 following paragraphs. Consult plates 2, 5, and 6 in connection with these 

 paragraphs. 



The values of S x are in general much larger for the two Lake Erie gages 

 than for the three Lake Michigan-Huron gages. The smallest value of S z , 

 at either Buffalo or Cleveland, shown in the table is 1.72 for north and south 

 winds at Cleveland. The largest value of * at any of the .three Lake 

 Michigan-Huron gages is . 95 for west and east winds at Milwaukee. Hence, 



