•88 Mr. E. Hatschek on some simple Deformations 



Fur. 4. 



surface of this prism will be 



and the increase in surface for the elongation L — 1 will be 



S OT being the surface of the minimum polyhedron, L e. the 

 cube. 



The curve defined by this equation is plotted in fig. 5, 



g g 



with L as abscissae and — ~ — — as ordinates. for L < 1, i. e. 



for compression, the ordinate grows rapidly and becomes c© 

 for L = 0. For L>1 the curve has a marked inflexion, and 

 the value of the abscissa at which the inflexion occurs is found 

 by two successive differentiations to be L= ^16 = 2*5198, 

 or an elongation of 152 per cent. This curve is marked 

 "P"for L>1. 



