522 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



paraffin series and frozen objects, it is not very successful with fresh or 

 hardened plant specimens. Fig. 140 explains the theory of Neuberger's 



Fig. 140. 



Fig. 141. 



machine. Two circles, a large one of radius M A (about 11 cm.), and a 

 small one of radius M L A (about 1 cm.), have external contact at A, at 



