308 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



Values of 



TABLE II. 



(-) Corresponding to Different Values of (ps- Co.m- 

 ^ /-opt. 



puTED from Equations (36) and (37). 



as 



opt 



These results are plotted in the curves of Figure 6, with ( r^ ) 



orclinates and <^3 as abscissas. The same curves give the values 



of ( -^ ) as ordinates provided the abscissas are read as values of <^4. 



\^ J opt 

 If the lower branch of the curve is used in obtaining the values 



of ( Y^ ) , the same branch must be employed in finding the corres- 



^ '^ 'opt 



ponding values of ( -^ ) . In like manner the top branch of the 



\A J opt 



curve 



