K\o\vLi:nr.i-:. 



NovEMisrr. ni: 



l-'lGl'Ki: 444. Liquid crystals of priia-.i/ow phcnctol in 

 natural light. 



e.xclusivelv with organic compounds and these only 

 of a particular type. \'orlander is the inxestigator 

 who has devoted special attention to this hranch of 

 the subject, having already disclosed many relation- 

 ships which may have much to do with the elucida- 

 tion of the phenomenon. 



The general conclusion at which he has arrived is 

 that the appearance of " liquid-crystals "" is invariably 

 associated with a linear structure of great length, 

 that is to say, with a structure which, when 

 represented three-dimensionally accordiiig to the 

 modern tetrahedron arrangement of the carbon 



li..iui. I ;.-,. Liiiind ci>.stal.-. u: j ..-..,, 



polarized light. 



affinities, approximates as closely as possible to a 

 straight line. The oft-recurring para-azoxyphenetol 

 w ill serve as an example — 



C. H.-, O 



N 



N — 



<) C, H-,. 



In the aliphatic division, therefore, only iionnal 

 compounds are eligible ; whilst in the aromatic series, 

 all but para substituted compounds are excluded. 

 Bending of the chain such as would be given by an 

 ortho- or meta-coni[iouiid. or tlic branching produced 



lir.cui 446. r.iiinid crystals of para-a/oxyplieiulol belwccM 

 crossed iiicols. 



li.-.iKi: 44; 



Liijiiid crystals of aniiiioniuin oh 

 crossed nicols. 



