348 



Fig. I, shews 'a) i * v n iaes, curves 28 



to 34, the curves e llxP , i.e. n, a- and j> are all positive : (b) 

 by broken medium lines, curves 34' to 40, the curves e nx_1 \ 

 i.e. ii and a 1 positive, and j> negative: (c) by thin continuous 

 lines, curves 40' to 46, the curves e _nxP i i.e. n negative and 

 p positive; and by thin broken lines, curves 46' to 52, the 



