Mac's and 400K diskettes

Hi, I'm working on an archive project and for the past 2 days I've gotten a Powermac 5260/100 back to life, gotten it hooked up to my network via its CS Slot Ethernet card (make not, the cable must have ALL pins connected, not just 1,2 & 3,6 - otherwise the cable isn't recognized as an active link by the Apple CS card... Got Appletalk protocol and Appleshare setup on my Win 2K3 server, now I'm connected, all is well in the universe... Oh, Mac has OS 8.1 installed... So I pop in a bunch of Corvus Mac diskettes from 84-85 so I'm assuming they are 400K ... no good, Mac won't read them, has no prob reading 800K diskettes, but won't read any of the Corvus disks... I am hoping the disks aren't bad (really hoping since they are next to impossible to find/replace) So, question is.... Does anyone know if Powermac's will read older 400K mac diskettes??? curt