Galactlc bars are thlcker than Inner parts of gas dlsks. Therefore
gas flow Into theback side of bars, relatlve to the dlrectlon of dlsc
rotation, Thls Idea, based on the equlllbrium condltlon for galactlc rotating subsystems Is used to Interprete forbldden line emlsslon In bar regione vhere gas Inflow supersonic.
The suggested interpretation of the phenomenon of dlfferent velocity fields in the linea of dlfferent excltetion first discovered in the Seyfert galaxy Mkn 744 • NGC 3786 is now checked in the case of another Seyfert NGC 1068. .The appllcabillty Is controled from the Inferences concemlng the sense of rotation of spiral arms In the galaxies. In both cases these agree wlth the earlier results obtalned from Independent methods t the arms In NGC 1068 are trailling, while in NGC 3786 they are leadlng. One of manifestations of the shock back along the front slde of bars Is the occurence of stralght dust lanes along the front aide. Applications of the method
to other observational problems are discussed.