A rotating coaxial cylinder apparatus capable of producing high laminar shear rates in simple liquids has been used in conjunction with standard optical components to measure the flow birefringence of 22 simple liquids in the n-alcohol, n-alkane and n-1- alkene homologous series, 16 of these being new determinations. The results are discussed in terms of molecular orientation, and, while the general requirements of both theories are satisfied, the Raman-Krishnan theory 1 yields values of a determinable bond polarizability parameter in good agreement with recent estimates, while the Peterlin-Stuart theory 2 does not.